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Research Article SimultaneousDetectionofAscorbicAcid,Dopamine,andUric AcidUsingaNovelElectrochemicalSensorBasedonPalladium Nanoparticles/Reduced Graphene Oxide Nanocomposite YuyunWei, 1 YangyangLiu, 1 ZhifangXu , 1 Shenjun Wang, 1 BoChen, 1 DiZhang , 2 andYuxinFang 1 1 Research Center of Experimental Acupuncture Science, College of Acumox and Tuina, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China 2 College of Pharmaceutical Engineering of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China Correspondence should be addressed to Di Zhang; [email protected] and Yuxin Fang; [email protected] Received 9 June 2020; Revised 19 November 2020; Accepted 30 November 2020; Published 17 December 2020 Academic Editor: Anastasios S. Economou Copyright © 2020 Yuyun Wei et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A fresh strategy based on two-step electrochemical reduction for the fabrication of palladium nanoparticles/reduced oxide nanocomposite-modified glass carbon electrode (PdNPs/rGO/GCE) was established in this study. Field emission scanning electron microscopy (FESEM) images showed that spherical PdNPs were evenly distributed on the surface of rGO-modified electrode (rGO/ GCE), and the introduction of PdNPs has no effect on the morphology of rGO. Electrochemical impedance spectroscopy (EIS) studies revealed that the conductivity of PdNPs/rGO/GCE was higher than that of rGO/GCE and bare GCE. e electrochemical performances of PdNPs/rGO/GCE sensor were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry using ascorbic acid (AA), dopamine (DA), and uric acid (UA) as analytes. At the optimized conditions, wide linear ranges of 0.5–3.5 mM (R 2 0.99), 3–15 μM(R 2 0.99) and 15–42 μM(R 2 0.99), and 0.3–1.4 mM (R 2 0.99) towards AA, DA, and UA in ternary mixture were observed, respectively. In addition to superior anti-interference capability, fast response (5s), excellent reproducibility, and good long-term stability were also given by this sensor. ese results suggested that PdNPs/rGO/GCE is promising for the simultaneous detection of AA, DA, and UA in practical application. 1.Introduction Noble metal nanoparticles, a kind of metal nanomaterial, are often used as enhancement elements in electrochemical sensors due to their excellent electrocatalytic activity, rapid electron transfer ability, strong stability, and good bio- compatibility [1–4]. Several noble metal nanoparticles, such as gold, silver, and platinum, are not suitable for com- mercialization due to their high cost and low availability. In contrast, palladium nanoparticles (PdNPs), an emerging noble metal nanoparticle, have been favored by researchers in recent years because of their higher abundance, lower cost, and well-resisted toxic intermediates [5–7]. However, the aggregation of PdNPs needs to be well addressed before mass application. Researches showed that carbon nanomaterials including carbon nanotubes, carbon dots, and graphene are beneficial to the dispersion of nanoparticles due to their unique structure, large specific surface area, and high catalytic ac- tivity [3, 8]. Among them, carbon dots are more suitable for fluorescent sensors due to their unique optical properties, while carbon nanotubes are prone to serious entanglement due to their inherent strong van der Waals interaction that requires additional dispersants. Neither of them can meet people’s demand for low-cost and high-performance bio- sensing platforms [9]. In practical application, high-quality Hindawi International Journal of Analytical Chemistry Volume 2020, Article ID 8812443, 13 pages https://doi.org/10.1155/2020/8812443
13

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Page 1: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

Research ArticleSimultaneous Detection of Ascorbic Acid Dopamine and UricAcid Using a Novel Electrochemical Sensor Based on PalladiumNanoparticlesReduced Graphene Oxide Nanocomposite

Yuyun Wei1 Yangyang Liu1 Zhifang Xu 1 Shenjun Wang1 Bo Chen1 Di Zhang 2

and Yuxin Fang 1

1Research Center of Experimental Acupuncture Science College of Acumox and TuinaTianjin University of Traditional Chinese Medicine Tianjin 301617 China2College of Pharmaceutical Engineering of Traditional Chinese Medicine Tianjin University of Traditional Chinese MedicineTianjin 301617 China

Correspondence should be addressed to Di Zhang 43987073qqcom and Yuxin Fang meng99_2006126com

Received 9 June 2020 Revised 19 November 2020 Accepted 30 November 2020 Published 17 December 2020

Academic Editor Anastasios S Economou

Copyright copy 2020 Yuyun Wei et al 1is is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

A fresh strategy based on two-step electrochemical reduction for the fabrication of palladium nanoparticlesreduced oxidenanocomposite-modified glass carbon electrode (PdNPsrGOGCE) was established in this study Field emission scanning electronmicroscopy (FESEM) images showed that spherical PdNPs were evenly distributed on the surface of rGO-modified electrode (rGOGCE) and the introduction of PdNPs has no effect on the morphology of rGO Electrochemical impedance spectroscopy (EIS)studies revealed that the conductivity of PdNPsrGOGCE was higher than that of rGOGCE and bare GCE 1e electrochemicalperformances of PdNPsrGOGCE sensor were investigated by cyclic voltammetry (CV) differential pulse voltammetry (DPV) andchronoamperometry using ascorbic acid (AA) dopamine (DA) and uric acid (UA) as analytes At the optimized conditions widelinear ranges of 05ndash35mM (R2 099) 3ndash15 μM(R2 099) and 15ndash42 μM(R2 099) and 03ndash14mM (R2 099) towards AA DAand UA in ternary mixture were observed respectively In addition to superior anti-interference capability fast response (le5 s)excellent reproducibility and good long-term stability were also given by this sensor1ese results suggested that PdNPsrGOGCE ispromising for the simultaneous detection of AA DA and UA in practical application

1 Introduction

Noble metal nanoparticles a kind of metal nanomaterial areoften used as enhancement elements in electrochemicalsensors due to their excellent electrocatalytic activity rapidelectron transfer ability strong stability and good bio-compatibility [1ndash4] Several noble metal nanoparticles suchas gold silver and platinum are not suitable for com-mercialization due to their high cost and low availability Incontrast palladium nanoparticles (PdNPs) an emergingnoble metal nanoparticle have been favored by researchersin recent years because of their higher abundance lowercost and well-resisted toxic intermediates [5ndash7] However

the aggregation of PdNPs needs to be well addressed beforemass application

Researches showed that carbon nanomaterials includingcarbon nanotubes carbon dots and graphene are beneficialto the dispersion of nanoparticles due to their uniquestructure large specific surface area and high catalytic ac-tivity [3 8] Among them carbon dots are more suitable forfluorescent sensors due to their unique optical propertieswhile carbon nanotubes are prone to serious entanglementdue to their inherent strong van der Waals interaction thatrequires additional dispersants Neither of them can meetpeoplersquos demand for low-cost and high-performance bio-sensing platforms [9] In practical application high-quality

HindawiInternational Journal of Analytical ChemistryVolume 2020 Article ID 8812443 13 pageshttpsdoiorg10115520208812443

graphene (reduced graphene oxide rGO) is often preparedby electrochemical reduction of graphene oxide (GO) whichis simple and cost-effective 1e residual oxygen functionalgroups and the recovery of the conjugated network makerGO possess hydrophilicity and high conductivity [10ndash12]Hence rGO is considered to be the most promising carbonnanomaterials for dispersing PdNPs [13ndash15]

As biological molecules of great significance to humanhealth the abnormal changes in ascorbic acid (AA)dopamine (DA) and uric acid (UA) in human body canbring serious threats including cancer Parkinsonrsquos dis-ease and leukemia [16ndash18] 1erefore the development ofa rapid and effective electrochemical senor for simulta-neous detection of these three substances is in urgentneed

Herein PdNPsrGOGCE was fabricated by facile two-step electrodeposition to detect AA DA and UA simul-taneously Although the preparation of PdNPsrGOnanocomposites has been reported [19ndash21] most of themare prepared through a multistep complex process whichnot only involves chemicals that may cause health andenvironmental risks but also contains long-time con-sumption In addition to good catalytic activity and rapidresponse (le5 s) the sensor prepared in this work alsoexhibited high reproducibility and stability

2 Experimental

21 Reagents AA (997) was obtained from LianxingBiotechnology (Tianjin) dopamine hydrochloride (DA98) was purchased from Sigma-Aldrich (Shanghai) UA(590ndash600) and palladium chloride were provided byRon Chemical Reagent Company (Tianjin) potassiumchloride (KCl 990) potassium ferricyanide sodiumdihydrogen phosphate (NaH2PO4 990) and disodiumhydrogen phosphate (Na2HPO4 ge990) were obtainedfrom Chemical Reagent Supply and Marketing company(Tianjin) GO (998) was provided by Xianfeng NanoMaterials Technology (Nanjing) Phosphate buffer (PB)solution with different pH values was prepared with themixed solution of NaH2PO4 and Na2HPO4 in a certainproportion Ultrapure water was used throughout allmeasurements

22 Apparatus High-resolution transmission electronmicroscopy (HRTEM) and energy-dispersive spectroscopy(EDS) were finished on a FEI-Talos-F200X equipped withan energy-dispersive spectrometer analyzer Field emissionscanning electron microscope (FESEM) images were ob-tained with a Nova NanoSEM 430 (FEI USA) Cyclicvoltammetry (CV) differential pulse voltammetry (DPV)and chronoamperometry measurements were performedusing a AMETEK PARSTAT 4000 electrochemical work-station (AMETEK Commercial Enterprise (Shanghai) CoLtd Beijing Branch) with a three-electrode system whilePdNPsrGOGCE platinum electrode and saturated cal-omel electrode (SCE) were used as a working electrodecounterelectrode and reference electrode respectively

KQ-600KDE high-power CNC ultrasonic cleaner waspurchased fromUltrasonic Instrument Co Ltd (Kunshan)Magnetic stirrer was provided by Ronghua InstrumentManufacturing Co Ltd (Changzhou)

23 Fabrication of PdNPsrGOGCE Before modificationthe bare GCE was successively polished with 1 μm03 μm and 005 μm Al2O3 slurry and then washed ul-trasonically in ultrapure water and ethanol to get a cleansurface

40mg of GO powder was completely dissolved in 40mLof ultrapure water under sonification for 60min to obtainGO solution 1e rGOGCE was fabricated in GO solutionby using the CV method between +1 and minus15V with a scanrate of 50mV middot sminus1 for 19 cycles after that the modifiedelectrode was washed with ultrapure water and dried atroom temperature

1en 00035 g palladium chloride was directly added in20mL of ultrapure water to obtain 1mM palladium chloridesolution and 6 μL of the solution was cast on the surface ofrGOGCE After the solution was totally dried the electrodewas immersed in 01M KCl solution and then treated byapplying minus07V for 1800 s for electrodeposition of PdNPsand then PdNPsrGOGCE was fabricated 1en the ob-tained sensor was washed with ultrapure water and dried forlater use (Scheme 1)

24 Electrochemical Measurements 1e EIS measurementswere performed from 10minus2 to 105Hz with an amplitude of+5V and a bias voltage of +024V DPV curves were ob-tained from minus15V to +15V at an amplitude of 50mV and apulse width of 02 s In addition since CV technology andchronoamperometry have been used many times in thispaper and the parameter settings of the same method weredifferent the corresponding parameter settings were in-troduced in the related experiments

3 Results and Discussion

31 Characterization of PdNPsrGO Nanocomposite 1eresults of FESEM and HRTEM of PdNPsrGO nano-composite are demonstrated in Figures 1(a)ndash1(c) It is ev-ident that the synthesized rGO has a typical folded structure[22 23] furthermore the PdNPs synthesized on the surfaceof the rGO were spherical and highly uniform in size whichnot only has no effect on the morphology of the rGO but alsohelps to increase the surface area of the electrode(Figures 1(a) and 1(b)) From the HRTEM image(Figure 1(c)) it was obtained that the PdNPs with an averagediameter less than 50 nm [24] were uniformly dispersed onthe surface of rGO which coincides with the result ofFigure 1(b) and literature [25] EDS characterization results(Figure S1) further confirm that the PdNPsrGO nano-composite was successfully prepared

CV and EIS were used to examine the electrochemicalbehavior of PdNPsrGOGCE in 20mM potassium ferri-cyanide solution containing 01M KCl CV curves wereobtained from minus06V to +08V with scan rate of 50mV sminus1

2 International Journal of Analytical Chemistry

for 3 weeks 1e active area of different electrodes wascalculated by following Randle Sevickrsquos equation [26]

A Ipa

269 times 1051113872 1113873Cn

32v12

D12

(1)

where Ipa is the anode peak current of different electrodes inCV experiments (Figure S2) C is the concentration ofpotassium ferricyanide solution (ie 20mM) n is thenumber of electrons v is the scan rate and D is the diffusioncoefficient 1e active surface ratio of bare GCE rGOGCEand PdNPsrGOGCE was calculated as 1 12 13 sug-gesting that the modification of rGO and PdNPsrGOnanocomposite on the surface of bare GCE helps to increasethe active area of the electrode that can improve the catalyticability of bare GCE

From Figure 1(d) the results of EIS were given in theform of Nyquist plot in which the diameter of high-frequency semicircle part represents the resistance ofcharge transfer (Rct) of the electrode surface [27] andlow-frequency linear part represents the diffusionprocess [28] Randlersquos circuit (inset of Figure 1(d)) was

chosen to fit the impedance data obtained 1e semi-circle diameter at PdNPsrGOGCE and rGOGCE wasmuch smaller than that of bare GCE (200Ω 400Ω and3000Ω respectively) indicating that the modification ofrGO and PdNPsrGO nanocomposites can all help topromote the electron transfer of bare GCE And theenhancement effect of PdNPsrGOGCE was greaterthan that of rGOGCE which can be attributed to theincrease in the contact area between the electrodesurface and the analytes after electrodeposition ofPdNPs 1e result of EIS was consistent with CVcharacterization (Figure S2)

32 Effect of pH 1e effect of pH of the supporting elec-trolyte (ie 01MPB) on the electrochemical behavior ofAA DA and UA was studied by DPV As shown inFigure 2(a) with the pH values varied from 64 to 76 thepeak current of AA and UA reaches the maximum at pH 72(blue line) while DA reaches at pH 68 (red line) To clearlyobserve the influence of pH values on the peak potential ofthese three substances the method of translation was used to

i-t

KCl solution

rGOGCE

6 μLPdCl2solution

PdNPsrGOGCE

PdNPs

GCE rGOGCE

CV

GOsoliution

Electrode surface

AA

DA

UA

Electrode surface

GCE

GCE GCE GCE GCE

PdNPs

HO

HO

HO

OO

OH

OH

NH2

OH

O

OO

HNHN

NHN

H

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

Curr

ent (

A)

ndash0000025

ndash0000030

ndash0000035

ndash04 ndash02 00Potential (V)

02 04 06

UAPdNPsrGOGCE

AADA

Scheme 1 Steps for fabrication of PdNPsrGOGCE

International Journal of Analytical Chemistry 3

separate the four curves As can be seen from Figure 2(b) thepeak potentials of AA DA and UA shift negatively withincreasing pH values and the peak potential differences ofAA-DA and DA-UA reach the maximum at pH 72 sug-gesting that protons were involved in the oxidation reactionof AA DA and UA [29]

Based on above 01M PB with pH value of 72 wasselected as the measurement medium in subsequentexperiments

33 Effect of Scan Rate 1e influence of scan rate on theredox behavior of 1mMAA 80 μMDA and 500 μMUAwasstudied in 01MPB using CV from minus06V to +06V for 3weeks (Figure 3) It can be seen that the oxidation peakcurrents of AA DA and UA and the reduction peak currentof DA were proportional to increasing scan rate from 50mv middot sminus1 to 250 mv middot sminus1 and the linear regression equationswere summarized as follows

AA Ipa 1064 + 0039v R2

0991113872 1113873

DA Ipa 4397 + 0036v R2

0991113872 1113873

Ipc minus1969 minus 0024v R2

0991113872 1113873

UA Ipa 5124 + 0028v R2

0991113872 1113873

(2)

where v is the scan rate and R2 is the correlation coefficient1e results proved that the electrochemical reaction of AADA and UA was adsorption-controlled process [30 31]

In addition there was no obvious reduction peak in AAand UA which may be related to the selection of detectionconcentration

34 Electrochemical Detection of AA DA and UA 1e an-alytical performances of PdNPsrGOGCE for AA DA andUA in 01MPB (pH 72) were examined by DPV at theoptimized conditions

(a) (b)

(c)

Zw

RS

Rct

Cdl

0 1000 2000 3000 4000 5000 6000 7000

2500

2000

1500

1000

500

0

Zero (ohms)

Zim

(ohm

s)

CB

A

(d)

Figure 1 (a) FESEM characterization of rGO (b) FESEM characterization of PdNPsrGO nanocomposites (c) HRETM characterization ofPdNPsrGO nanocomposites (d) EIS characterization of bare GCE (A) rGOGCE (B) and PdNPsrGOGCE (C) in 20mM potassiumferricyanide solution containing 01M KCl

4 International Journal of Analytical Chemistry

ndash0000004

ndash0000006

ndash0000008

ndash0000010

ndash0000012

ndash0000014

ndash0000016

ndash0000018

ndash0000020

ndash0000022

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

pH 64pH 68

pH 72pH 76

(a)

000003

000002

000001

000000

ndash000001

ndash000002

ndash000003

ndash000004

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

pH 64

pH 68

pH 72

pH 76AA DA UA

(b)

Figure 2 (a) DPVs of 075mM AA 30 μM DA and 125mM UA at PdNPsrGOGCE at various pH values (black 64 red 68 blue 72green 76) (b) DPV curves after translation

0602 04ndash04 ndash02 00ndash06Potential (V)

ndash000003

ndash000002

ndash000001

000000

000001

000002

Curr

ent (

A)

250 mVs

50 mVs

AA

(a)

Curr

ent (μA

)

AA

50 100 150 200 250Scan rate (mV)

20

18

16

14

12

R2 = 099406

(b)

ndash000003

ndash000002

ndash000001

000000

000001

000002

Curr

ent (

A)

250 mVs

50 mVs

DA

0602 04ndash04 ndash02 00ndash06Potential (V)

(c)

Curr

ent (μA

)

DA

50 100 150 200 250Scan rate (mV)

R2 = 099504

R2 = 099348

15

10

5

0

ndash5

(d)

Figure 3 Continued

International Journal of Analytical Chemistry 5

ndash000003

ndash000002

ndash000001

000000

000001

000002Cu

rren

t (A

)250 mVs

50 mVs

UA

0602 04ndash04 ndash02 00ndash06Potential (V)

(e)

Curr

ent (μA

)

UA

50 100 150 200 250Scan rate (mV)

13

12

11

10

9

8

7

6

R2 = 099712

(f )

Figure 3 CV voltammograms of AA (a) DA (c) and UA (e) on PdNPsrGOGCE at 50 100 150 200 and 250mVmiddotsminus1 scan ratesrelationship between the peak current of (b) AA (d) DA and (f) UA and the scan rates

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

03 mM

30 mM

AA

(a)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash800 5 10 15 20 25 30

Concentration (mmolL)

Curr

ent (μA

)

R2 = 098613

R2 = 098753

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

ndash0000030

ndash0000035ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

3 μM

170 μM

DA

(c)

0

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

Concentration (μmolL)

Curr

ent (μA

)

R2 = 098578

R2 = 098815

ndash20 0 20 40 60 80 100 120 140 160 180

DA

(d)

Figure 4 Continued

6 International Journal of Analytical Chemistry

As can be seen fromFigure 4 at PdNPsrGOGCE the peakcurrent signals of AA DA and UA were all gradually increasedwith their rising levels and achieve a good linear relationship inthe concentration ranges of 03ndash7mM and 8ndash20mM 3ndash50μMand 60ndash170μM and 005ndash1mM and 15ndash45mM with detec-tion limits of 01mM 1μM and 1667μM (SN 3) respec-tively In addition from Figure 4(a) it is worth noting that withthe increase in AA concentration the peak potential of AAshifts to the right indicating that protons have participated inthe electrode reaction process of AA [32] Meanwhile the peakshape of AA gradually widens which is consistent with previousstudies [33ndash35] that may be related to the excessive concen-tration of AA At low AA levels the local AA on the electrodesurface was rapidly catalyzed and the response was fast At highAA concentrations a large amount of AA was adsorbed on theelectrode surface leading to the reduction of the active sites onthe surface of electrode prolonging the catalytic time of PdNPsrGOGCE for AA thus slowing down the catalytic process andwidening the peak shape [36] 1e oxidation mechanisms ofAA DA and UA may be inferred as follows (1) electrostaticinteraction between positive DA and negative functional groupson PdNPsrGOGCE surface (2) the hydrogen bond interac-tion between the hydroxyl groups of AA DA and UA and theoxygen-containing functional groups on the surface of PdNPsrGOGCE

Figures 5 and 6 exhibit the selective and simultaneousdetection results of AA DA and UA It is worth mentioningthat the selective detection was carried out by changing theconcentrations of target species while keeping the other twosubstances at constant in a mixture of AA DA and UA Ascan be observed there exists three well-separated potentialpeaks corresponding to AA DA and UA either in selectiveor simultaneous detection and the presence of the other twospecies did not produce significant impact on the currentsignal of the target analyte suggesting that PdNPsrGOGCE possesses good separation capacity toward AA DAand UA 1e detailed results are presented in Table 1Compared with individual detection the linear range of AA

DA and UA under the same concentration range and thesensitivity of PdNPsrGOGCE toward these three analytesall produced a negligible change either in selective or si-multaneous detection

In addition it can be observed from Figure 5(a) thatwith the increase in AA concentration in addition to theincreasing AA current the detection currents of DA andUA were also increased which is consistent with previousliteratures [28 29 37ndash41] that can be related to the ad-sorption of DA and UA on the electrode surface [42] 1ehigher concentration of AA on electrode surface contin-uously reacts with the oxidation products of DA and UAresulting in the regeneration of DA and UA thus in-creasing the current [43 44] Moreover from Figures 4(a)5(a) and 6(a) it is worthy to note that the oxidationvoltages of AA in these three experiments were not thesame which may be related to the concentration range ofAA and the interaction between AA and DA and UA[43 44]

As shown in Table 2 although most of previous worksshowed higher sensitivity toward AA and UA than PdNPsrGOGCE from the perspective of sensitivity toward DAand linear range PdNPsrGOGCE still occupies a uniqueadvantage in the simultaneous detection of AA DA andUA

1e above results showed that the developed sensor has agood application value in the detection of AA DA and UA

35 Reproducibility and Stability of the SensorReproducibility and stability are also crucial indicators forthe evaluation of the electrochemical performances of thedeveloped sensor

1e reproducibility of PdNPsrGOGCE was studied byDPV using six sensors that were prepared under the sameconditions to detect 1mM AA 10 μM DA and 25mM UAin 01MPB respectively and the results were exhibited inthe form of histogram (Figure 7(a)) 1e relative standard

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

005 mM

9 mM

UA

(e)

Concentration (mmolL)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash80

Curr

ent (μA

)

R2 = 098509

R2 = 098728

UA

0 2 4 6 8 10

(f)

Figure 4 DPVs of different concentrations of (a) AA (c) DA and (e) UA on PdNPsrGOGCE in 01MPB (pH 72) calibration plots for (b)AA (d) DA and (f) UA

International Journal of Analytical Chemistry 7

deviation (RSD) of the DPV responses of AA DA and UAwas calculated as 098 208 and 06 respectively re-vealing that the proposed sensor has high reproducibility

Chronoamperometry was used to access the stability ofPdNPsrGOGCE toward 1mMAA 20 μMDA and 05mM

UA in 01MPB for 2000 s at +06V From Figures 7(b)ndash7(d)the current response of these three analytes reached a steadystate in a short time and the changes over a long period werenegligible which suggested that this sensor is suitable forlong-term detection of AA DA and UA

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

075 mM

5 mM

(a)

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

ndash40

ndash450 1 2 3 4 5

Curr

ent (μA

)

Concentration (mmolL)

R2 = 099921

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

13 μM

61 μM

(c)

ndash8

ndash10

ndash12

ndash14

ndash16

ndash18

ndash20

ndash2210 20 30 40 50 60

Curr

ent (μA

)

Concentration (μmolL)

R2 = 099489

DA

(d)

000000

ndash000002

ndash000004

ndash000006

ndash000008

ndash000010

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

01 mM

75 mM

(e)

0

ndash20

ndash40

ndash60

ndash80

ndash1000 1 2 3 4 5 6 7 8

Curr

ent (μA

)

Concentration (mmolL)

R2 = 098595

R2 = 098619

UA

(f )

Figure 5 DPVs of different concentrations of (a) AA in the presence of 20 μMDA and 05mM UA (c) DA in the presence of 15mM AAand 05mM UA and (e) UA in the presence of 075mM AA and 10 μM DA Calibration plots for (b) AA (d) DA and (f) UA

8 International Journal of Analytical Chemistry

36 Study of Anti-Interference Ability Lastly to evaluate theanti-interference ability of PdNPsrGOGCE the interfer-ence of Na+ (d) Clminus (e) Mg2+ (f) SO42minus (g) and glucose (h)with 100-fold concentration in the detection of 1mM AA(a) 50 μM DA (b) and 01mM UA (c) in 01MPB wasconducted by chronoamperometry at a constant potential of+06V for 800 s As shown in Figure 8 with the addition ofAA DA and UA the current signal of PdNPsrGOGCEincreased rapidly with response times of 5 s 5 s and 3 srespectively and the interferents did not produce obvious

effects on the current signal of AA DA and UA As a resultthis proposed sensor was of excellent anti-interferenceability and practical application value

37 Real Samples Detection In order to demonstrate theapplicability of the proposedmethod different concentrations ofAA DA and UA are doped into the human serum samples bythe standard addition method 1e DPV experimental resultsare shown in Table S11e recoveries of the spiked samples were

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

Delt

a I (F

-R) (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

025 mM

35 mM 01 mM

14 mM

3 μM

42 μM

(a)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

00 05 10 15 20 25 30 35 40Concentration (mmolL)

AA

Curr

ent (μA

)

R2 = 099187

(b)

Concentration (μmolL)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

0 10 20 30 40 50

Curr

ent (μA

)

R2 = 099598

R2 = 099248

DA

(c)

Concentration (mmolL)00 02 04 06 08 10 12 14 16

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

Curr

ent (μA

)

R2 = 098765

UA

(d)

Figure 6 DPV curves of different concentrations of AA DA and UA (a) calibration plots for (b) AA (c) DA and (d) UA

Table 1 Analytical parameters for individual selective and simultaneous detection of AA DA and UA at PdNPsrGOGCE

Analytical parameter Analyte Individual detection Selective detection Simultaneous detection

Linear range (μM)AA 300ndash7000 8000ndash20000 750ndash5000 500ndash3500DA 3ndash50 60ndash170 13ndash61 3ndash15 15ndash42UA 50ndash1000 1500ndash4500 500ndash4000 4500ndash7500 300ndash1400

Sensitivity (μA middot μMminus1 middot cmminus2)AA 0069 0028 0107 0079DA 4300 1443 3254 10893 6083UA 0416 0118 0194 0049 0481

International Journal of Analytical Chemistry 9

Table 2 Comparison of different electrodes in the simultaneous detection of AA DA and UA

Electrode pHLinear range (μM)

Sensitivity (μA middot μMminus1 middot cmminus2) RefAA DA UA

MgO nanobeltsGCE 50 25ndash15 25ndash1500198 0028

0125ndash757908

05ndash3 5ndash30283 0962 [30]

SnO2chitosanGCE 70 20ndash2200127

01ndash182773

1ndash1002391 [45]

3DGHa-AuNPsbGCE 70 10ndash7000217

02ndash303897

1ndash601703 [46]

AuNPsbMoS2 nanosheetsGCE 40 12ndash8000481

10ndash3000979

8ndash9000465 [47]

Pd3Pt1cPDDAd-rGOGCE 74 40ndash12000359

4ndash2000639

4ndash4000498 [48]

CBeGCE 70 191ndash3780214

0599ndash1181570

101ndash140680 [49]

PtNP-AuSnfCFPg 70 200ndash120000004

05ndash1000017

25ndash50000003 [50]

PdNPsrGOGCE 72 500ndash35000079

3ndash15 15ndash4210893 6083

300ndash14000481 1is work

a three dimensional graphene hydrogel b gold nanoparticles c Pd-Pt bimetallic nanoparticles d poly(diallyldimethylammonium chloride) e nano-structured carbon black f Pt nanoparticle-modified nanoporous AuSn g Ni-buffered flexible carbon fiber paper

80

70

60

50

40

30

20

10

01 2 3 4 5 6

Electrode number

Curr

ent (μA

)

AADAUA

(a)

0 500 1000 1500 2000Elapsed time (s)

0000007

0000006

0000005

0000004

0000003

0000002

0000001

0000000

Curr

ent (

A)

AA

(b)

0 500 1000 1500 2000Elapsed time (s)

00000035

00000030

00000025

00000020

00000015

00000010

00000005

00000000

Curr

ent (

A)

DA

(c)

0 500 1000 1500 2000Elapsed time (s)

000008

000007

000006

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

UA

(d)

Figure 7 (a) Reproducibility of CQDs-rGOGCE stability of (b) 1mM AA (c) 20 μM DA and (d) 05mM UA

10 International Journal of Analytical Chemistry

detected within the range of 966ndash1085 suggesting theapplicability of the prepared sensor to real samples

4 Conclusions

In summary this paper has proposed a novel approach forthe synthesis of PdNPsrGO nanocomposite by two-step CVelectrodeposition the increased surface area of as-preparedmaterial has contributed to improve the contact probabilitybetween electrode surface and analytes thus elevating thecatalytic activity of the modified electrode which wasconfirmed using CV and EIS After optimizing the experi-mental conditions the sensor showed excellent separationability and fast response for AA DA and UA and has stronganti-interference ability for some common interferingsubstances Besides good reproducibility and stability werealso obtained by this sensor 1e above results revealed thatPdNPsrGOGCE can be a good candidate in the sensingapplication of AA DA and UA in the future

Data Availability

1e generated or analyzed data used to support the findingsof this study are included within the article

Conflicts of Interest

1e authors declare that they have no conflicts of interest

Acknowledgments

1is study was financially supported by the National KeyRampD Program of China (no 2019YFC1709000) NationalNatural Science Foundation of China (NSFC) (nos81973944 and 81503636) National SampT Major Project (no2018ZX09201011) and Youth Talent Promotion Project ofthe China Association for Science and Technology (no 2019-2021ZGZJXH-QNRC001)

Supplementary Materials

Figure S1 EDS characterization of PdNPsrGO nano-composites Figure S2 CV characterization of bare GCE (a)rGOGCE (b) and PdNPsrGOGCE (c) in 20mM potas-sium ferricyanide solution containing 01M KCl Table S1detection of AA DA and UA in real samples (n 3)(Supplementary Materials)

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

Curr

ent (

A)

0 200 400 600 800Time (s)

5 s

180 200 220 240 260 280 300

000005000004000003000002000001000000

Time (s)

AA

d

a

e f g h

(a)

Curr

ent (

A)

Curr

ent (

A)

0000012

0000010

0000008

0000006

0000004

0000002

0000000

ndash00000020 200 400 600 800

Time (s)

5 s180 200 220 240 260 280 300

000002000000180000016000001400000120000010

000008000006000004000002000000

ndash000002

Time (s)

DA

d

b

e f g h

(b)

Curr

ent (

A)Cu

rren

t (A

)

0 200 400 600 800Time (s)

00000010

00000008

00000006

00000004

00000002

00000000

ndash00000002

3 s

200 220 240 260 280Time (s)

000000100000000800000006000000040000000200000000

ndash00000002

UA

d e f g h

c

(c)

Figure 8 Amperometric responses of 1mM AA (a) 50 μM DA (b) and 01mM UA (c) in the presence of 100-fold concentration ofinterferents

International Journal of Analytical Chemistry 11

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 2: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

graphene (reduced graphene oxide rGO) is often preparedby electrochemical reduction of graphene oxide (GO) whichis simple and cost-effective 1e residual oxygen functionalgroups and the recovery of the conjugated network makerGO possess hydrophilicity and high conductivity [10ndash12]Hence rGO is considered to be the most promising carbonnanomaterials for dispersing PdNPs [13ndash15]

As biological molecules of great significance to humanhealth the abnormal changes in ascorbic acid (AA)dopamine (DA) and uric acid (UA) in human body canbring serious threats including cancer Parkinsonrsquos dis-ease and leukemia [16ndash18] 1erefore the development ofa rapid and effective electrochemical senor for simulta-neous detection of these three substances is in urgentneed

Herein PdNPsrGOGCE was fabricated by facile two-step electrodeposition to detect AA DA and UA simul-taneously Although the preparation of PdNPsrGOnanocomposites has been reported [19ndash21] most of themare prepared through a multistep complex process whichnot only involves chemicals that may cause health andenvironmental risks but also contains long-time con-sumption In addition to good catalytic activity and rapidresponse (le5 s) the sensor prepared in this work alsoexhibited high reproducibility and stability

2 Experimental

21 Reagents AA (997) was obtained from LianxingBiotechnology (Tianjin) dopamine hydrochloride (DA98) was purchased from Sigma-Aldrich (Shanghai) UA(590ndash600) and palladium chloride were provided byRon Chemical Reagent Company (Tianjin) potassiumchloride (KCl 990) potassium ferricyanide sodiumdihydrogen phosphate (NaH2PO4 990) and disodiumhydrogen phosphate (Na2HPO4 ge990) were obtainedfrom Chemical Reagent Supply and Marketing company(Tianjin) GO (998) was provided by Xianfeng NanoMaterials Technology (Nanjing) Phosphate buffer (PB)solution with different pH values was prepared with themixed solution of NaH2PO4 and Na2HPO4 in a certainproportion Ultrapure water was used throughout allmeasurements

22 Apparatus High-resolution transmission electronmicroscopy (HRTEM) and energy-dispersive spectroscopy(EDS) were finished on a FEI-Talos-F200X equipped withan energy-dispersive spectrometer analyzer Field emissionscanning electron microscope (FESEM) images were ob-tained with a Nova NanoSEM 430 (FEI USA) Cyclicvoltammetry (CV) differential pulse voltammetry (DPV)and chronoamperometry measurements were performedusing a AMETEK PARSTAT 4000 electrochemical work-station (AMETEK Commercial Enterprise (Shanghai) CoLtd Beijing Branch) with a three-electrode system whilePdNPsrGOGCE platinum electrode and saturated cal-omel electrode (SCE) were used as a working electrodecounterelectrode and reference electrode respectively

KQ-600KDE high-power CNC ultrasonic cleaner waspurchased fromUltrasonic Instrument Co Ltd (Kunshan)Magnetic stirrer was provided by Ronghua InstrumentManufacturing Co Ltd (Changzhou)

23 Fabrication of PdNPsrGOGCE Before modificationthe bare GCE was successively polished with 1 μm03 μm and 005 μm Al2O3 slurry and then washed ul-trasonically in ultrapure water and ethanol to get a cleansurface

40mg of GO powder was completely dissolved in 40mLof ultrapure water under sonification for 60min to obtainGO solution 1e rGOGCE was fabricated in GO solutionby using the CV method between +1 and minus15V with a scanrate of 50mV middot sminus1 for 19 cycles after that the modifiedelectrode was washed with ultrapure water and dried atroom temperature

1en 00035 g palladium chloride was directly added in20mL of ultrapure water to obtain 1mM palladium chloridesolution and 6 μL of the solution was cast on the surface ofrGOGCE After the solution was totally dried the electrodewas immersed in 01M KCl solution and then treated byapplying minus07V for 1800 s for electrodeposition of PdNPsand then PdNPsrGOGCE was fabricated 1en the ob-tained sensor was washed with ultrapure water and dried forlater use (Scheme 1)

24 Electrochemical Measurements 1e EIS measurementswere performed from 10minus2 to 105Hz with an amplitude of+5V and a bias voltage of +024V DPV curves were ob-tained from minus15V to +15V at an amplitude of 50mV and apulse width of 02 s In addition since CV technology andchronoamperometry have been used many times in thispaper and the parameter settings of the same method weredifferent the corresponding parameter settings were in-troduced in the related experiments

3 Results and Discussion

31 Characterization of PdNPsrGO Nanocomposite 1eresults of FESEM and HRTEM of PdNPsrGO nano-composite are demonstrated in Figures 1(a)ndash1(c) It is ev-ident that the synthesized rGO has a typical folded structure[22 23] furthermore the PdNPs synthesized on the surfaceof the rGO were spherical and highly uniform in size whichnot only has no effect on the morphology of the rGO but alsohelps to increase the surface area of the electrode(Figures 1(a) and 1(b)) From the HRTEM image(Figure 1(c)) it was obtained that the PdNPs with an averagediameter less than 50 nm [24] were uniformly dispersed onthe surface of rGO which coincides with the result ofFigure 1(b) and literature [25] EDS characterization results(Figure S1) further confirm that the PdNPsrGO nano-composite was successfully prepared

CV and EIS were used to examine the electrochemicalbehavior of PdNPsrGOGCE in 20mM potassium ferri-cyanide solution containing 01M KCl CV curves wereobtained from minus06V to +08V with scan rate of 50mV sminus1

2 International Journal of Analytical Chemistry

for 3 weeks 1e active area of different electrodes wascalculated by following Randle Sevickrsquos equation [26]

A Ipa

269 times 1051113872 1113873Cn

32v12

D12

(1)

where Ipa is the anode peak current of different electrodes inCV experiments (Figure S2) C is the concentration ofpotassium ferricyanide solution (ie 20mM) n is thenumber of electrons v is the scan rate and D is the diffusioncoefficient 1e active surface ratio of bare GCE rGOGCEand PdNPsrGOGCE was calculated as 1 12 13 sug-gesting that the modification of rGO and PdNPsrGOnanocomposite on the surface of bare GCE helps to increasethe active area of the electrode that can improve the catalyticability of bare GCE

From Figure 1(d) the results of EIS were given in theform of Nyquist plot in which the diameter of high-frequency semicircle part represents the resistance ofcharge transfer (Rct) of the electrode surface [27] andlow-frequency linear part represents the diffusionprocess [28] Randlersquos circuit (inset of Figure 1(d)) was

chosen to fit the impedance data obtained 1e semi-circle diameter at PdNPsrGOGCE and rGOGCE wasmuch smaller than that of bare GCE (200Ω 400Ω and3000Ω respectively) indicating that the modification ofrGO and PdNPsrGO nanocomposites can all help topromote the electron transfer of bare GCE And theenhancement effect of PdNPsrGOGCE was greaterthan that of rGOGCE which can be attributed to theincrease in the contact area between the electrodesurface and the analytes after electrodeposition ofPdNPs 1e result of EIS was consistent with CVcharacterization (Figure S2)

32 Effect of pH 1e effect of pH of the supporting elec-trolyte (ie 01MPB) on the electrochemical behavior ofAA DA and UA was studied by DPV As shown inFigure 2(a) with the pH values varied from 64 to 76 thepeak current of AA and UA reaches the maximum at pH 72(blue line) while DA reaches at pH 68 (red line) To clearlyobserve the influence of pH values on the peak potential ofthese three substances the method of translation was used to

i-t

KCl solution

rGOGCE

6 μLPdCl2solution

PdNPsrGOGCE

PdNPs

GCE rGOGCE

CV

GOsoliution

Electrode surface

AA

DA

UA

Electrode surface

GCE

GCE GCE GCE GCE

PdNPs

HO

HO

HO

OO

OH

OH

NH2

OH

O

OO

HNHN

NHN

H

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

Curr

ent (

A)

ndash0000025

ndash0000030

ndash0000035

ndash04 ndash02 00Potential (V)

02 04 06

UAPdNPsrGOGCE

AADA

Scheme 1 Steps for fabrication of PdNPsrGOGCE

International Journal of Analytical Chemistry 3

separate the four curves As can be seen from Figure 2(b) thepeak potentials of AA DA and UA shift negatively withincreasing pH values and the peak potential differences ofAA-DA and DA-UA reach the maximum at pH 72 sug-gesting that protons were involved in the oxidation reactionof AA DA and UA [29]

Based on above 01M PB with pH value of 72 wasselected as the measurement medium in subsequentexperiments

33 Effect of Scan Rate 1e influence of scan rate on theredox behavior of 1mMAA 80 μMDA and 500 μMUAwasstudied in 01MPB using CV from minus06V to +06V for 3weeks (Figure 3) It can be seen that the oxidation peakcurrents of AA DA and UA and the reduction peak currentof DA were proportional to increasing scan rate from 50mv middot sminus1 to 250 mv middot sminus1 and the linear regression equationswere summarized as follows

AA Ipa 1064 + 0039v R2

0991113872 1113873

DA Ipa 4397 + 0036v R2

0991113872 1113873

Ipc minus1969 minus 0024v R2

0991113872 1113873

UA Ipa 5124 + 0028v R2

0991113872 1113873

(2)

where v is the scan rate and R2 is the correlation coefficient1e results proved that the electrochemical reaction of AADA and UA was adsorption-controlled process [30 31]

In addition there was no obvious reduction peak in AAand UA which may be related to the selection of detectionconcentration

34 Electrochemical Detection of AA DA and UA 1e an-alytical performances of PdNPsrGOGCE for AA DA andUA in 01MPB (pH 72) were examined by DPV at theoptimized conditions

(a) (b)

(c)

Zw

RS

Rct

Cdl

0 1000 2000 3000 4000 5000 6000 7000

2500

2000

1500

1000

500

0

Zero (ohms)

Zim

(ohm

s)

CB

A

(d)

Figure 1 (a) FESEM characterization of rGO (b) FESEM characterization of PdNPsrGO nanocomposites (c) HRETM characterization ofPdNPsrGO nanocomposites (d) EIS characterization of bare GCE (A) rGOGCE (B) and PdNPsrGOGCE (C) in 20mM potassiumferricyanide solution containing 01M KCl

4 International Journal of Analytical Chemistry

ndash0000004

ndash0000006

ndash0000008

ndash0000010

ndash0000012

ndash0000014

ndash0000016

ndash0000018

ndash0000020

ndash0000022

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

pH 64pH 68

pH 72pH 76

(a)

000003

000002

000001

000000

ndash000001

ndash000002

ndash000003

ndash000004

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

pH 64

pH 68

pH 72

pH 76AA DA UA

(b)

Figure 2 (a) DPVs of 075mM AA 30 μM DA and 125mM UA at PdNPsrGOGCE at various pH values (black 64 red 68 blue 72green 76) (b) DPV curves after translation

0602 04ndash04 ndash02 00ndash06Potential (V)

ndash000003

ndash000002

ndash000001

000000

000001

000002

Curr

ent (

A)

250 mVs

50 mVs

AA

(a)

Curr

ent (μA

)

AA

50 100 150 200 250Scan rate (mV)

20

18

16

14

12

R2 = 099406

(b)

ndash000003

ndash000002

ndash000001

000000

000001

000002

Curr

ent (

A)

250 mVs

50 mVs

DA

0602 04ndash04 ndash02 00ndash06Potential (V)

(c)

Curr

ent (μA

)

DA

50 100 150 200 250Scan rate (mV)

R2 = 099504

R2 = 099348

15

10

5

0

ndash5

(d)

Figure 3 Continued

International Journal of Analytical Chemistry 5

ndash000003

ndash000002

ndash000001

000000

000001

000002Cu

rren

t (A

)250 mVs

50 mVs

UA

0602 04ndash04 ndash02 00ndash06Potential (V)

(e)

Curr

ent (μA

)

UA

50 100 150 200 250Scan rate (mV)

13

12

11

10

9

8

7

6

R2 = 099712

(f )

Figure 3 CV voltammograms of AA (a) DA (c) and UA (e) on PdNPsrGOGCE at 50 100 150 200 and 250mVmiddotsminus1 scan ratesrelationship between the peak current of (b) AA (d) DA and (f) UA and the scan rates

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

03 mM

30 mM

AA

(a)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash800 5 10 15 20 25 30

Concentration (mmolL)

Curr

ent (μA

)

R2 = 098613

R2 = 098753

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

ndash0000030

ndash0000035ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

3 μM

170 μM

DA

(c)

0

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

Concentration (μmolL)

Curr

ent (μA

)

R2 = 098578

R2 = 098815

ndash20 0 20 40 60 80 100 120 140 160 180

DA

(d)

Figure 4 Continued

6 International Journal of Analytical Chemistry

As can be seen fromFigure 4 at PdNPsrGOGCE the peakcurrent signals of AA DA and UA were all gradually increasedwith their rising levels and achieve a good linear relationship inthe concentration ranges of 03ndash7mM and 8ndash20mM 3ndash50μMand 60ndash170μM and 005ndash1mM and 15ndash45mM with detec-tion limits of 01mM 1μM and 1667μM (SN 3) respec-tively In addition from Figure 4(a) it is worth noting that withthe increase in AA concentration the peak potential of AAshifts to the right indicating that protons have participated inthe electrode reaction process of AA [32] Meanwhile the peakshape of AA gradually widens which is consistent with previousstudies [33ndash35] that may be related to the excessive concen-tration of AA At low AA levels the local AA on the electrodesurface was rapidly catalyzed and the response was fast At highAA concentrations a large amount of AA was adsorbed on theelectrode surface leading to the reduction of the active sites onthe surface of electrode prolonging the catalytic time of PdNPsrGOGCE for AA thus slowing down the catalytic process andwidening the peak shape [36] 1e oxidation mechanisms ofAA DA and UA may be inferred as follows (1) electrostaticinteraction between positive DA and negative functional groupson PdNPsrGOGCE surface (2) the hydrogen bond interac-tion between the hydroxyl groups of AA DA and UA and theoxygen-containing functional groups on the surface of PdNPsrGOGCE

Figures 5 and 6 exhibit the selective and simultaneousdetection results of AA DA and UA It is worth mentioningthat the selective detection was carried out by changing theconcentrations of target species while keeping the other twosubstances at constant in a mixture of AA DA and UA Ascan be observed there exists three well-separated potentialpeaks corresponding to AA DA and UA either in selectiveor simultaneous detection and the presence of the other twospecies did not produce significant impact on the currentsignal of the target analyte suggesting that PdNPsrGOGCE possesses good separation capacity toward AA DAand UA 1e detailed results are presented in Table 1Compared with individual detection the linear range of AA

DA and UA under the same concentration range and thesensitivity of PdNPsrGOGCE toward these three analytesall produced a negligible change either in selective or si-multaneous detection

In addition it can be observed from Figure 5(a) thatwith the increase in AA concentration in addition to theincreasing AA current the detection currents of DA andUA were also increased which is consistent with previousliteratures [28 29 37ndash41] that can be related to the ad-sorption of DA and UA on the electrode surface [42] 1ehigher concentration of AA on electrode surface contin-uously reacts with the oxidation products of DA and UAresulting in the regeneration of DA and UA thus in-creasing the current [43 44] Moreover from Figures 4(a)5(a) and 6(a) it is worthy to note that the oxidationvoltages of AA in these three experiments were not thesame which may be related to the concentration range ofAA and the interaction between AA and DA and UA[43 44]

As shown in Table 2 although most of previous worksshowed higher sensitivity toward AA and UA than PdNPsrGOGCE from the perspective of sensitivity toward DAand linear range PdNPsrGOGCE still occupies a uniqueadvantage in the simultaneous detection of AA DA andUA

1e above results showed that the developed sensor has agood application value in the detection of AA DA and UA

35 Reproducibility and Stability of the SensorReproducibility and stability are also crucial indicators forthe evaluation of the electrochemical performances of thedeveloped sensor

1e reproducibility of PdNPsrGOGCE was studied byDPV using six sensors that were prepared under the sameconditions to detect 1mM AA 10 μM DA and 25mM UAin 01MPB respectively and the results were exhibited inthe form of histogram (Figure 7(a)) 1e relative standard

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

005 mM

9 mM

UA

(e)

Concentration (mmolL)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash80

Curr

ent (μA

)

R2 = 098509

R2 = 098728

UA

0 2 4 6 8 10

(f)

Figure 4 DPVs of different concentrations of (a) AA (c) DA and (e) UA on PdNPsrGOGCE in 01MPB (pH 72) calibration plots for (b)AA (d) DA and (f) UA

International Journal of Analytical Chemistry 7

deviation (RSD) of the DPV responses of AA DA and UAwas calculated as 098 208 and 06 respectively re-vealing that the proposed sensor has high reproducibility

Chronoamperometry was used to access the stability ofPdNPsrGOGCE toward 1mMAA 20 μMDA and 05mM

UA in 01MPB for 2000 s at +06V From Figures 7(b)ndash7(d)the current response of these three analytes reached a steadystate in a short time and the changes over a long period werenegligible which suggested that this sensor is suitable forlong-term detection of AA DA and UA

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

075 mM

5 mM

(a)

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

ndash40

ndash450 1 2 3 4 5

Curr

ent (μA

)

Concentration (mmolL)

R2 = 099921

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

13 μM

61 μM

(c)

ndash8

ndash10

ndash12

ndash14

ndash16

ndash18

ndash20

ndash2210 20 30 40 50 60

Curr

ent (μA

)

Concentration (μmolL)

R2 = 099489

DA

(d)

000000

ndash000002

ndash000004

ndash000006

ndash000008

ndash000010

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

01 mM

75 mM

(e)

0

ndash20

ndash40

ndash60

ndash80

ndash1000 1 2 3 4 5 6 7 8

Curr

ent (μA

)

Concentration (mmolL)

R2 = 098595

R2 = 098619

UA

(f )

Figure 5 DPVs of different concentrations of (a) AA in the presence of 20 μMDA and 05mM UA (c) DA in the presence of 15mM AAand 05mM UA and (e) UA in the presence of 075mM AA and 10 μM DA Calibration plots for (b) AA (d) DA and (f) UA

8 International Journal of Analytical Chemistry

36 Study of Anti-Interference Ability Lastly to evaluate theanti-interference ability of PdNPsrGOGCE the interfer-ence of Na+ (d) Clminus (e) Mg2+ (f) SO42minus (g) and glucose (h)with 100-fold concentration in the detection of 1mM AA(a) 50 μM DA (b) and 01mM UA (c) in 01MPB wasconducted by chronoamperometry at a constant potential of+06V for 800 s As shown in Figure 8 with the addition ofAA DA and UA the current signal of PdNPsrGOGCEincreased rapidly with response times of 5 s 5 s and 3 srespectively and the interferents did not produce obvious

effects on the current signal of AA DA and UA As a resultthis proposed sensor was of excellent anti-interferenceability and practical application value

37 Real Samples Detection In order to demonstrate theapplicability of the proposedmethod different concentrations ofAA DA and UA are doped into the human serum samples bythe standard addition method 1e DPV experimental resultsare shown in Table S11e recoveries of the spiked samples were

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

Delt

a I (F

-R) (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

025 mM

35 mM 01 mM

14 mM

3 μM

42 μM

(a)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

00 05 10 15 20 25 30 35 40Concentration (mmolL)

AA

Curr

ent (μA

)

R2 = 099187

(b)

Concentration (μmolL)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

0 10 20 30 40 50

Curr

ent (μA

)

R2 = 099598

R2 = 099248

DA

(c)

Concentration (mmolL)00 02 04 06 08 10 12 14 16

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

Curr

ent (μA

)

R2 = 098765

UA

(d)

Figure 6 DPV curves of different concentrations of AA DA and UA (a) calibration plots for (b) AA (c) DA and (d) UA

Table 1 Analytical parameters for individual selective and simultaneous detection of AA DA and UA at PdNPsrGOGCE

Analytical parameter Analyte Individual detection Selective detection Simultaneous detection

Linear range (μM)AA 300ndash7000 8000ndash20000 750ndash5000 500ndash3500DA 3ndash50 60ndash170 13ndash61 3ndash15 15ndash42UA 50ndash1000 1500ndash4500 500ndash4000 4500ndash7500 300ndash1400

Sensitivity (μA middot μMminus1 middot cmminus2)AA 0069 0028 0107 0079DA 4300 1443 3254 10893 6083UA 0416 0118 0194 0049 0481

International Journal of Analytical Chemistry 9

Table 2 Comparison of different electrodes in the simultaneous detection of AA DA and UA

Electrode pHLinear range (μM)

Sensitivity (μA middot μMminus1 middot cmminus2) RefAA DA UA

MgO nanobeltsGCE 50 25ndash15 25ndash1500198 0028

0125ndash757908

05ndash3 5ndash30283 0962 [30]

SnO2chitosanGCE 70 20ndash2200127

01ndash182773

1ndash1002391 [45]

3DGHa-AuNPsbGCE 70 10ndash7000217

02ndash303897

1ndash601703 [46]

AuNPsbMoS2 nanosheetsGCE 40 12ndash8000481

10ndash3000979

8ndash9000465 [47]

Pd3Pt1cPDDAd-rGOGCE 74 40ndash12000359

4ndash2000639

4ndash4000498 [48]

CBeGCE 70 191ndash3780214

0599ndash1181570

101ndash140680 [49]

PtNP-AuSnfCFPg 70 200ndash120000004

05ndash1000017

25ndash50000003 [50]

PdNPsrGOGCE 72 500ndash35000079

3ndash15 15ndash4210893 6083

300ndash14000481 1is work

a three dimensional graphene hydrogel b gold nanoparticles c Pd-Pt bimetallic nanoparticles d poly(diallyldimethylammonium chloride) e nano-structured carbon black f Pt nanoparticle-modified nanoporous AuSn g Ni-buffered flexible carbon fiber paper

80

70

60

50

40

30

20

10

01 2 3 4 5 6

Electrode number

Curr

ent (μA

)

AADAUA

(a)

0 500 1000 1500 2000Elapsed time (s)

0000007

0000006

0000005

0000004

0000003

0000002

0000001

0000000

Curr

ent (

A)

AA

(b)

0 500 1000 1500 2000Elapsed time (s)

00000035

00000030

00000025

00000020

00000015

00000010

00000005

00000000

Curr

ent (

A)

DA

(c)

0 500 1000 1500 2000Elapsed time (s)

000008

000007

000006

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

UA

(d)

Figure 7 (a) Reproducibility of CQDs-rGOGCE stability of (b) 1mM AA (c) 20 μM DA and (d) 05mM UA

10 International Journal of Analytical Chemistry

detected within the range of 966ndash1085 suggesting theapplicability of the prepared sensor to real samples

4 Conclusions

In summary this paper has proposed a novel approach forthe synthesis of PdNPsrGO nanocomposite by two-step CVelectrodeposition the increased surface area of as-preparedmaterial has contributed to improve the contact probabilitybetween electrode surface and analytes thus elevating thecatalytic activity of the modified electrode which wasconfirmed using CV and EIS After optimizing the experi-mental conditions the sensor showed excellent separationability and fast response for AA DA and UA and has stronganti-interference ability for some common interferingsubstances Besides good reproducibility and stability werealso obtained by this sensor 1e above results revealed thatPdNPsrGOGCE can be a good candidate in the sensingapplication of AA DA and UA in the future

Data Availability

1e generated or analyzed data used to support the findingsof this study are included within the article

Conflicts of Interest

1e authors declare that they have no conflicts of interest

Acknowledgments

1is study was financially supported by the National KeyRampD Program of China (no 2019YFC1709000) NationalNatural Science Foundation of China (NSFC) (nos81973944 and 81503636) National SampT Major Project (no2018ZX09201011) and Youth Talent Promotion Project ofthe China Association for Science and Technology (no 2019-2021ZGZJXH-QNRC001)

Supplementary Materials

Figure S1 EDS characterization of PdNPsrGO nano-composites Figure S2 CV characterization of bare GCE (a)rGOGCE (b) and PdNPsrGOGCE (c) in 20mM potas-sium ferricyanide solution containing 01M KCl Table S1detection of AA DA and UA in real samples (n 3)(Supplementary Materials)

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

Curr

ent (

A)

0 200 400 600 800Time (s)

5 s

180 200 220 240 260 280 300

000005000004000003000002000001000000

Time (s)

AA

d

a

e f g h

(a)

Curr

ent (

A)

Curr

ent (

A)

0000012

0000010

0000008

0000006

0000004

0000002

0000000

ndash00000020 200 400 600 800

Time (s)

5 s180 200 220 240 260 280 300

000002000000180000016000001400000120000010

000008000006000004000002000000

ndash000002

Time (s)

DA

d

b

e f g h

(b)

Curr

ent (

A)Cu

rren

t (A

)

0 200 400 600 800Time (s)

00000010

00000008

00000006

00000004

00000002

00000000

ndash00000002

3 s

200 220 240 260 280Time (s)

000000100000000800000006000000040000000200000000

ndash00000002

UA

d e f g h

c

(c)

Figure 8 Amperometric responses of 1mM AA (a) 50 μM DA (b) and 01mM UA (c) in the presence of 100-fold concentration ofinterferents

International Journal of Analytical Chemistry 11

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 3: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

for 3 weeks 1e active area of different electrodes wascalculated by following Randle Sevickrsquos equation [26]

A Ipa

269 times 1051113872 1113873Cn

32v12

D12

(1)

where Ipa is the anode peak current of different electrodes inCV experiments (Figure S2) C is the concentration ofpotassium ferricyanide solution (ie 20mM) n is thenumber of electrons v is the scan rate and D is the diffusioncoefficient 1e active surface ratio of bare GCE rGOGCEand PdNPsrGOGCE was calculated as 1 12 13 sug-gesting that the modification of rGO and PdNPsrGOnanocomposite on the surface of bare GCE helps to increasethe active area of the electrode that can improve the catalyticability of bare GCE

From Figure 1(d) the results of EIS were given in theform of Nyquist plot in which the diameter of high-frequency semicircle part represents the resistance ofcharge transfer (Rct) of the electrode surface [27] andlow-frequency linear part represents the diffusionprocess [28] Randlersquos circuit (inset of Figure 1(d)) was

chosen to fit the impedance data obtained 1e semi-circle diameter at PdNPsrGOGCE and rGOGCE wasmuch smaller than that of bare GCE (200Ω 400Ω and3000Ω respectively) indicating that the modification ofrGO and PdNPsrGO nanocomposites can all help topromote the electron transfer of bare GCE And theenhancement effect of PdNPsrGOGCE was greaterthan that of rGOGCE which can be attributed to theincrease in the contact area between the electrodesurface and the analytes after electrodeposition ofPdNPs 1e result of EIS was consistent with CVcharacterization (Figure S2)

32 Effect of pH 1e effect of pH of the supporting elec-trolyte (ie 01MPB) on the electrochemical behavior ofAA DA and UA was studied by DPV As shown inFigure 2(a) with the pH values varied from 64 to 76 thepeak current of AA and UA reaches the maximum at pH 72(blue line) while DA reaches at pH 68 (red line) To clearlyobserve the influence of pH values on the peak potential ofthese three substances the method of translation was used to

i-t

KCl solution

rGOGCE

6 μLPdCl2solution

PdNPsrGOGCE

PdNPs

GCE rGOGCE

CV

GOsoliution

Electrode surface

AA

DA

UA

Electrode surface

GCE

GCE GCE GCE GCE

PdNPs

HO

HO

HO

OO

OH

OH

NH2

OH

O

OO

HNHN

NHN

H

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

Curr

ent (

A)

ndash0000025

ndash0000030

ndash0000035

ndash04 ndash02 00Potential (V)

02 04 06

UAPdNPsrGOGCE

AADA

Scheme 1 Steps for fabrication of PdNPsrGOGCE

International Journal of Analytical Chemistry 3

separate the four curves As can be seen from Figure 2(b) thepeak potentials of AA DA and UA shift negatively withincreasing pH values and the peak potential differences ofAA-DA and DA-UA reach the maximum at pH 72 sug-gesting that protons were involved in the oxidation reactionof AA DA and UA [29]

Based on above 01M PB with pH value of 72 wasselected as the measurement medium in subsequentexperiments

33 Effect of Scan Rate 1e influence of scan rate on theredox behavior of 1mMAA 80 μMDA and 500 μMUAwasstudied in 01MPB using CV from minus06V to +06V for 3weeks (Figure 3) It can be seen that the oxidation peakcurrents of AA DA and UA and the reduction peak currentof DA were proportional to increasing scan rate from 50mv middot sminus1 to 250 mv middot sminus1 and the linear regression equationswere summarized as follows

AA Ipa 1064 + 0039v R2

0991113872 1113873

DA Ipa 4397 + 0036v R2

0991113872 1113873

Ipc minus1969 minus 0024v R2

0991113872 1113873

UA Ipa 5124 + 0028v R2

0991113872 1113873

(2)

where v is the scan rate and R2 is the correlation coefficient1e results proved that the electrochemical reaction of AADA and UA was adsorption-controlled process [30 31]

In addition there was no obvious reduction peak in AAand UA which may be related to the selection of detectionconcentration

34 Electrochemical Detection of AA DA and UA 1e an-alytical performances of PdNPsrGOGCE for AA DA andUA in 01MPB (pH 72) were examined by DPV at theoptimized conditions

(a) (b)

(c)

Zw

RS

Rct

Cdl

0 1000 2000 3000 4000 5000 6000 7000

2500

2000

1500

1000

500

0

Zero (ohms)

Zim

(ohm

s)

CB

A

(d)

Figure 1 (a) FESEM characterization of rGO (b) FESEM characterization of PdNPsrGO nanocomposites (c) HRETM characterization ofPdNPsrGO nanocomposites (d) EIS characterization of bare GCE (A) rGOGCE (B) and PdNPsrGOGCE (C) in 20mM potassiumferricyanide solution containing 01M KCl

4 International Journal of Analytical Chemistry

ndash0000004

ndash0000006

ndash0000008

ndash0000010

ndash0000012

ndash0000014

ndash0000016

ndash0000018

ndash0000020

ndash0000022

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

pH 64pH 68

pH 72pH 76

(a)

000003

000002

000001

000000

ndash000001

ndash000002

ndash000003

ndash000004

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

pH 64

pH 68

pH 72

pH 76AA DA UA

(b)

Figure 2 (a) DPVs of 075mM AA 30 μM DA and 125mM UA at PdNPsrGOGCE at various pH values (black 64 red 68 blue 72green 76) (b) DPV curves after translation

0602 04ndash04 ndash02 00ndash06Potential (V)

ndash000003

ndash000002

ndash000001

000000

000001

000002

Curr

ent (

A)

250 mVs

50 mVs

AA

(a)

Curr

ent (μA

)

AA

50 100 150 200 250Scan rate (mV)

20

18

16

14

12

R2 = 099406

(b)

ndash000003

ndash000002

ndash000001

000000

000001

000002

Curr

ent (

A)

250 mVs

50 mVs

DA

0602 04ndash04 ndash02 00ndash06Potential (V)

(c)

Curr

ent (μA

)

DA

50 100 150 200 250Scan rate (mV)

R2 = 099504

R2 = 099348

15

10

5

0

ndash5

(d)

Figure 3 Continued

International Journal of Analytical Chemistry 5

ndash000003

ndash000002

ndash000001

000000

000001

000002Cu

rren

t (A

)250 mVs

50 mVs

UA

0602 04ndash04 ndash02 00ndash06Potential (V)

(e)

Curr

ent (μA

)

UA

50 100 150 200 250Scan rate (mV)

13

12

11

10

9

8

7

6

R2 = 099712

(f )

Figure 3 CV voltammograms of AA (a) DA (c) and UA (e) on PdNPsrGOGCE at 50 100 150 200 and 250mVmiddotsminus1 scan ratesrelationship between the peak current of (b) AA (d) DA and (f) UA and the scan rates

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

03 mM

30 mM

AA

(a)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash800 5 10 15 20 25 30

Concentration (mmolL)

Curr

ent (μA

)

R2 = 098613

R2 = 098753

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

ndash0000030

ndash0000035ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

3 μM

170 μM

DA

(c)

0

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

Concentration (μmolL)

Curr

ent (μA

)

R2 = 098578

R2 = 098815

ndash20 0 20 40 60 80 100 120 140 160 180

DA

(d)

Figure 4 Continued

6 International Journal of Analytical Chemistry

As can be seen fromFigure 4 at PdNPsrGOGCE the peakcurrent signals of AA DA and UA were all gradually increasedwith their rising levels and achieve a good linear relationship inthe concentration ranges of 03ndash7mM and 8ndash20mM 3ndash50μMand 60ndash170μM and 005ndash1mM and 15ndash45mM with detec-tion limits of 01mM 1μM and 1667μM (SN 3) respec-tively In addition from Figure 4(a) it is worth noting that withthe increase in AA concentration the peak potential of AAshifts to the right indicating that protons have participated inthe electrode reaction process of AA [32] Meanwhile the peakshape of AA gradually widens which is consistent with previousstudies [33ndash35] that may be related to the excessive concen-tration of AA At low AA levels the local AA on the electrodesurface was rapidly catalyzed and the response was fast At highAA concentrations a large amount of AA was adsorbed on theelectrode surface leading to the reduction of the active sites onthe surface of electrode prolonging the catalytic time of PdNPsrGOGCE for AA thus slowing down the catalytic process andwidening the peak shape [36] 1e oxidation mechanisms ofAA DA and UA may be inferred as follows (1) electrostaticinteraction between positive DA and negative functional groupson PdNPsrGOGCE surface (2) the hydrogen bond interac-tion between the hydroxyl groups of AA DA and UA and theoxygen-containing functional groups on the surface of PdNPsrGOGCE

Figures 5 and 6 exhibit the selective and simultaneousdetection results of AA DA and UA It is worth mentioningthat the selective detection was carried out by changing theconcentrations of target species while keeping the other twosubstances at constant in a mixture of AA DA and UA Ascan be observed there exists three well-separated potentialpeaks corresponding to AA DA and UA either in selectiveor simultaneous detection and the presence of the other twospecies did not produce significant impact on the currentsignal of the target analyte suggesting that PdNPsrGOGCE possesses good separation capacity toward AA DAand UA 1e detailed results are presented in Table 1Compared with individual detection the linear range of AA

DA and UA under the same concentration range and thesensitivity of PdNPsrGOGCE toward these three analytesall produced a negligible change either in selective or si-multaneous detection

In addition it can be observed from Figure 5(a) thatwith the increase in AA concentration in addition to theincreasing AA current the detection currents of DA andUA were also increased which is consistent with previousliteratures [28 29 37ndash41] that can be related to the ad-sorption of DA and UA on the electrode surface [42] 1ehigher concentration of AA on electrode surface contin-uously reacts with the oxidation products of DA and UAresulting in the regeneration of DA and UA thus in-creasing the current [43 44] Moreover from Figures 4(a)5(a) and 6(a) it is worthy to note that the oxidationvoltages of AA in these three experiments were not thesame which may be related to the concentration range ofAA and the interaction between AA and DA and UA[43 44]

As shown in Table 2 although most of previous worksshowed higher sensitivity toward AA and UA than PdNPsrGOGCE from the perspective of sensitivity toward DAand linear range PdNPsrGOGCE still occupies a uniqueadvantage in the simultaneous detection of AA DA andUA

1e above results showed that the developed sensor has agood application value in the detection of AA DA and UA

35 Reproducibility and Stability of the SensorReproducibility and stability are also crucial indicators forthe evaluation of the electrochemical performances of thedeveloped sensor

1e reproducibility of PdNPsrGOGCE was studied byDPV using six sensors that were prepared under the sameconditions to detect 1mM AA 10 μM DA and 25mM UAin 01MPB respectively and the results were exhibited inthe form of histogram (Figure 7(a)) 1e relative standard

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

005 mM

9 mM

UA

(e)

Concentration (mmolL)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash80

Curr

ent (μA

)

R2 = 098509

R2 = 098728

UA

0 2 4 6 8 10

(f)

Figure 4 DPVs of different concentrations of (a) AA (c) DA and (e) UA on PdNPsrGOGCE in 01MPB (pH 72) calibration plots for (b)AA (d) DA and (f) UA

International Journal of Analytical Chemistry 7

deviation (RSD) of the DPV responses of AA DA and UAwas calculated as 098 208 and 06 respectively re-vealing that the proposed sensor has high reproducibility

Chronoamperometry was used to access the stability ofPdNPsrGOGCE toward 1mMAA 20 μMDA and 05mM

UA in 01MPB for 2000 s at +06V From Figures 7(b)ndash7(d)the current response of these three analytes reached a steadystate in a short time and the changes over a long period werenegligible which suggested that this sensor is suitable forlong-term detection of AA DA and UA

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

075 mM

5 mM

(a)

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

ndash40

ndash450 1 2 3 4 5

Curr

ent (μA

)

Concentration (mmolL)

R2 = 099921

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

13 μM

61 μM

(c)

ndash8

ndash10

ndash12

ndash14

ndash16

ndash18

ndash20

ndash2210 20 30 40 50 60

Curr

ent (μA

)

Concentration (μmolL)

R2 = 099489

DA

(d)

000000

ndash000002

ndash000004

ndash000006

ndash000008

ndash000010

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

01 mM

75 mM

(e)

0

ndash20

ndash40

ndash60

ndash80

ndash1000 1 2 3 4 5 6 7 8

Curr

ent (μA

)

Concentration (mmolL)

R2 = 098595

R2 = 098619

UA

(f )

Figure 5 DPVs of different concentrations of (a) AA in the presence of 20 μMDA and 05mM UA (c) DA in the presence of 15mM AAand 05mM UA and (e) UA in the presence of 075mM AA and 10 μM DA Calibration plots for (b) AA (d) DA and (f) UA

8 International Journal of Analytical Chemistry

36 Study of Anti-Interference Ability Lastly to evaluate theanti-interference ability of PdNPsrGOGCE the interfer-ence of Na+ (d) Clminus (e) Mg2+ (f) SO42minus (g) and glucose (h)with 100-fold concentration in the detection of 1mM AA(a) 50 μM DA (b) and 01mM UA (c) in 01MPB wasconducted by chronoamperometry at a constant potential of+06V for 800 s As shown in Figure 8 with the addition ofAA DA and UA the current signal of PdNPsrGOGCEincreased rapidly with response times of 5 s 5 s and 3 srespectively and the interferents did not produce obvious

effects on the current signal of AA DA and UA As a resultthis proposed sensor was of excellent anti-interferenceability and practical application value

37 Real Samples Detection In order to demonstrate theapplicability of the proposedmethod different concentrations ofAA DA and UA are doped into the human serum samples bythe standard addition method 1e DPV experimental resultsare shown in Table S11e recoveries of the spiked samples were

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

Delt

a I (F

-R) (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

025 mM

35 mM 01 mM

14 mM

3 μM

42 μM

(a)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

00 05 10 15 20 25 30 35 40Concentration (mmolL)

AA

Curr

ent (μA

)

R2 = 099187

(b)

Concentration (μmolL)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

0 10 20 30 40 50

Curr

ent (μA

)

R2 = 099598

R2 = 099248

DA

(c)

Concentration (mmolL)00 02 04 06 08 10 12 14 16

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

Curr

ent (μA

)

R2 = 098765

UA

(d)

Figure 6 DPV curves of different concentrations of AA DA and UA (a) calibration plots for (b) AA (c) DA and (d) UA

Table 1 Analytical parameters for individual selective and simultaneous detection of AA DA and UA at PdNPsrGOGCE

Analytical parameter Analyte Individual detection Selective detection Simultaneous detection

Linear range (μM)AA 300ndash7000 8000ndash20000 750ndash5000 500ndash3500DA 3ndash50 60ndash170 13ndash61 3ndash15 15ndash42UA 50ndash1000 1500ndash4500 500ndash4000 4500ndash7500 300ndash1400

Sensitivity (μA middot μMminus1 middot cmminus2)AA 0069 0028 0107 0079DA 4300 1443 3254 10893 6083UA 0416 0118 0194 0049 0481

International Journal of Analytical Chemistry 9

Table 2 Comparison of different electrodes in the simultaneous detection of AA DA and UA

Electrode pHLinear range (μM)

Sensitivity (μA middot μMminus1 middot cmminus2) RefAA DA UA

MgO nanobeltsGCE 50 25ndash15 25ndash1500198 0028

0125ndash757908

05ndash3 5ndash30283 0962 [30]

SnO2chitosanGCE 70 20ndash2200127

01ndash182773

1ndash1002391 [45]

3DGHa-AuNPsbGCE 70 10ndash7000217

02ndash303897

1ndash601703 [46]

AuNPsbMoS2 nanosheetsGCE 40 12ndash8000481

10ndash3000979

8ndash9000465 [47]

Pd3Pt1cPDDAd-rGOGCE 74 40ndash12000359

4ndash2000639

4ndash4000498 [48]

CBeGCE 70 191ndash3780214

0599ndash1181570

101ndash140680 [49]

PtNP-AuSnfCFPg 70 200ndash120000004

05ndash1000017

25ndash50000003 [50]

PdNPsrGOGCE 72 500ndash35000079

3ndash15 15ndash4210893 6083

300ndash14000481 1is work

a three dimensional graphene hydrogel b gold nanoparticles c Pd-Pt bimetallic nanoparticles d poly(diallyldimethylammonium chloride) e nano-structured carbon black f Pt nanoparticle-modified nanoporous AuSn g Ni-buffered flexible carbon fiber paper

80

70

60

50

40

30

20

10

01 2 3 4 5 6

Electrode number

Curr

ent (μA

)

AADAUA

(a)

0 500 1000 1500 2000Elapsed time (s)

0000007

0000006

0000005

0000004

0000003

0000002

0000001

0000000

Curr

ent (

A)

AA

(b)

0 500 1000 1500 2000Elapsed time (s)

00000035

00000030

00000025

00000020

00000015

00000010

00000005

00000000

Curr

ent (

A)

DA

(c)

0 500 1000 1500 2000Elapsed time (s)

000008

000007

000006

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

UA

(d)

Figure 7 (a) Reproducibility of CQDs-rGOGCE stability of (b) 1mM AA (c) 20 μM DA and (d) 05mM UA

10 International Journal of Analytical Chemistry

detected within the range of 966ndash1085 suggesting theapplicability of the prepared sensor to real samples

4 Conclusions

In summary this paper has proposed a novel approach forthe synthesis of PdNPsrGO nanocomposite by two-step CVelectrodeposition the increased surface area of as-preparedmaterial has contributed to improve the contact probabilitybetween electrode surface and analytes thus elevating thecatalytic activity of the modified electrode which wasconfirmed using CV and EIS After optimizing the experi-mental conditions the sensor showed excellent separationability and fast response for AA DA and UA and has stronganti-interference ability for some common interferingsubstances Besides good reproducibility and stability werealso obtained by this sensor 1e above results revealed thatPdNPsrGOGCE can be a good candidate in the sensingapplication of AA DA and UA in the future

Data Availability

1e generated or analyzed data used to support the findingsof this study are included within the article

Conflicts of Interest

1e authors declare that they have no conflicts of interest

Acknowledgments

1is study was financially supported by the National KeyRampD Program of China (no 2019YFC1709000) NationalNatural Science Foundation of China (NSFC) (nos81973944 and 81503636) National SampT Major Project (no2018ZX09201011) and Youth Talent Promotion Project ofthe China Association for Science and Technology (no 2019-2021ZGZJXH-QNRC001)

Supplementary Materials

Figure S1 EDS characterization of PdNPsrGO nano-composites Figure S2 CV characterization of bare GCE (a)rGOGCE (b) and PdNPsrGOGCE (c) in 20mM potas-sium ferricyanide solution containing 01M KCl Table S1detection of AA DA and UA in real samples (n 3)(Supplementary Materials)

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

Curr

ent (

A)

0 200 400 600 800Time (s)

5 s

180 200 220 240 260 280 300

000005000004000003000002000001000000

Time (s)

AA

d

a

e f g h

(a)

Curr

ent (

A)

Curr

ent (

A)

0000012

0000010

0000008

0000006

0000004

0000002

0000000

ndash00000020 200 400 600 800

Time (s)

5 s180 200 220 240 260 280 300

000002000000180000016000001400000120000010

000008000006000004000002000000

ndash000002

Time (s)

DA

d

b

e f g h

(b)

Curr

ent (

A)Cu

rren

t (A

)

0 200 400 600 800Time (s)

00000010

00000008

00000006

00000004

00000002

00000000

ndash00000002

3 s

200 220 240 260 280Time (s)

000000100000000800000006000000040000000200000000

ndash00000002

UA

d e f g h

c

(c)

Figure 8 Amperometric responses of 1mM AA (a) 50 μM DA (b) and 01mM UA (c) in the presence of 100-fold concentration ofinterferents

International Journal of Analytical Chemistry 11

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 4: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

separate the four curves As can be seen from Figure 2(b) thepeak potentials of AA DA and UA shift negatively withincreasing pH values and the peak potential differences ofAA-DA and DA-UA reach the maximum at pH 72 sug-gesting that protons were involved in the oxidation reactionof AA DA and UA [29]

Based on above 01M PB with pH value of 72 wasselected as the measurement medium in subsequentexperiments

33 Effect of Scan Rate 1e influence of scan rate on theredox behavior of 1mMAA 80 μMDA and 500 μMUAwasstudied in 01MPB using CV from minus06V to +06V for 3weeks (Figure 3) It can be seen that the oxidation peakcurrents of AA DA and UA and the reduction peak currentof DA were proportional to increasing scan rate from 50mv middot sminus1 to 250 mv middot sminus1 and the linear regression equationswere summarized as follows

AA Ipa 1064 + 0039v R2

0991113872 1113873

DA Ipa 4397 + 0036v R2

0991113872 1113873

Ipc minus1969 minus 0024v R2

0991113872 1113873

UA Ipa 5124 + 0028v R2

0991113872 1113873

(2)

where v is the scan rate and R2 is the correlation coefficient1e results proved that the electrochemical reaction of AADA and UA was adsorption-controlled process [30 31]

In addition there was no obvious reduction peak in AAand UA which may be related to the selection of detectionconcentration

34 Electrochemical Detection of AA DA and UA 1e an-alytical performances of PdNPsrGOGCE for AA DA andUA in 01MPB (pH 72) were examined by DPV at theoptimized conditions

(a) (b)

(c)

Zw

RS

Rct

Cdl

0 1000 2000 3000 4000 5000 6000 7000

2500

2000

1500

1000

500

0

Zero (ohms)

Zim

(ohm

s)

CB

A

(d)

Figure 1 (a) FESEM characterization of rGO (b) FESEM characterization of PdNPsrGO nanocomposites (c) HRETM characterization ofPdNPsrGO nanocomposites (d) EIS characterization of bare GCE (A) rGOGCE (B) and PdNPsrGOGCE (C) in 20mM potassiumferricyanide solution containing 01M KCl

4 International Journal of Analytical Chemistry

ndash0000004

ndash0000006

ndash0000008

ndash0000010

ndash0000012

ndash0000014

ndash0000016

ndash0000018

ndash0000020

ndash0000022

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

pH 64pH 68

pH 72pH 76

(a)

000003

000002

000001

000000

ndash000001

ndash000002

ndash000003

ndash000004

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

pH 64

pH 68

pH 72

pH 76AA DA UA

(b)

Figure 2 (a) DPVs of 075mM AA 30 μM DA and 125mM UA at PdNPsrGOGCE at various pH values (black 64 red 68 blue 72green 76) (b) DPV curves after translation

0602 04ndash04 ndash02 00ndash06Potential (V)

ndash000003

ndash000002

ndash000001

000000

000001

000002

Curr

ent (

A)

250 mVs

50 mVs

AA

(a)

Curr

ent (μA

)

AA

50 100 150 200 250Scan rate (mV)

20

18

16

14

12

R2 = 099406

(b)

ndash000003

ndash000002

ndash000001

000000

000001

000002

Curr

ent (

A)

250 mVs

50 mVs

DA

0602 04ndash04 ndash02 00ndash06Potential (V)

(c)

Curr

ent (μA

)

DA

50 100 150 200 250Scan rate (mV)

R2 = 099504

R2 = 099348

15

10

5

0

ndash5

(d)

Figure 3 Continued

International Journal of Analytical Chemistry 5

ndash000003

ndash000002

ndash000001

000000

000001

000002Cu

rren

t (A

)250 mVs

50 mVs

UA

0602 04ndash04 ndash02 00ndash06Potential (V)

(e)

Curr

ent (μA

)

UA

50 100 150 200 250Scan rate (mV)

13

12

11

10

9

8

7

6

R2 = 099712

(f )

Figure 3 CV voltammograms of AA (a) DA (c) and UA (e) on PdNPsrGOGCE at 50 100 150 200 and 250mVmiddotsminus1 scan ratesrelationship between the peak current of (b) AA (d) DA and (f) UA and the scan rates

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

03 mM

30 mM

AA

(a)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash800 5 10 15 20 25 30

Concentration (mmolL)

Curr

ent (μA

)

R2 = 098613

R2 = 098753

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

ndash0000030

ndash0000035ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

3 μM

170 μM

DA

(c)

0

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

Concentration (μmolL)

Curr

ent (μA

)

R2 = 098578

R2 = 098815

ndash20 0 20 40 60 80 100 120 140 160 180

DA

(d)

Figure 4 Continued

6 International Journal of Analytical Chemistry

As can be seen fromFigure 4 at PdNPsrGOGCE the peakcurrent signals of AA DA and UA were all gradually increasedwith their rising levels and achieve a good linear relationship inthe concentration ranges of 03ndash7mM and 8ndash20mM 3ndash50μMand 60ndash170μM and 005ndash1mM and 15ndash45mM with detec-tion limits of 01mM 1μM and 1667μM (SN 3) respec-tively In addition from Figure 4(a) it is worth noting that withthe increase in AA concentration the peak potential of AAshifts to the right indicating that protons have participated inthe electrode reaction process of AA [32] Meanwhile the peakshape of AA gradually widens which is consistent with previousstudies [33ndash35] that may be related to the excessive concen-tration of AA At low AA levels the local AA on the electrodesurface was rapidly catalyzed and the response was fast At highAA concentrations a large amount of AA was adsorbed on theelectrode surface leading to the reduction of the active sites onthe surface of electrode prolonging the catalytic time of PdNPsrGOGCE for AA thus slowing down the catalytic process andwidening the peak shape [36] 1e oxidation mechanisms ofAA DA and UA may be inferred as follows (1) electrostaticinteraction between positive DA and negative functional groupson PdNPsrGOGCE surface (2) the hydrogen bond interac-tion between the hydroxyl groups of AA DA and UA and theoxygen-containing functional groups on the surface of PdNPsrGOGCE

Figures 5 and 6 exhibit the selective and simultaneousdetection results of AA DA and UA It is worth mentioningthat the selective detection was carried out by changing theconcentrations of target species while keeping the other twosubstances at constant in a mixture of AA DA and UA Ascan be observed there exists three well-separated potentialpeaks corresponding to AA DA and UA either in selectiveor simultaneous detection and the presence of the other twospecies did not produce significant impact on the currentsignal of the target analyte suggesting that PdNPsrGOGCE possesses good separation capacity toward AA DAand UA 1e detailed results are presented in Table 1Compared with individual detection the linear range of AA

DA and UA under the same concentration range and thesensitivity of PdNPsrGOGCE toward these three analytesall produced a negligible change either in selective or si-multaneous detection

In addition it can be observed from Figure 5(a) thatwith the increase in AA concentration in addition to theincreasing AA current the detection currents of DA andUA were also increased which is consistent with previousliteratures [28 29 37ndash41] that can be related to the ad-sorption of DA and UA on the electrode surface [42] 1ehigher concentration of AA on electrode surface contin-uously reacts with the oxidation products of DA and UAresulting in the regeneration of DA and UA thus in-creasing the current [43 44] Moreover from Figures 4(a)5(a) and 6(a) it is worthy to note that the oxidationvoltages of AA in these three experiments were not thesame which may be related to the concentration range ofAA and the interaction between AA and DA and UA[43 44]

As shown in Table 2 although most of previous worksshowed higher sensitivity toward AA and UA than PdNPsrGOGCE from the perspective of sensitivity toward DAand linear range PdNPsrGOGCE still occupies a uniqueadvantage in the simultaneous detection of AA DA andUA

1e above results showed that the developed sensor has agood application value in the detection of AA DA and UA

35 Reproducibility and Stability of the SensorReproducibility and stability are also crucial indicators forthe evaluation of the electrochemical performances of thedeveloped sensor

1e reproducibility of PdNPsrGOGCE was studied byDPV using six sensors that were prepared under the sameconditions to detect 1mM AA 10 μM DA and 25mM UAin 01MPB respectively and the results were exhibited inthe form of histogram (Figure 7(a)) 1e relative standard

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

005 mM

9 mM

UA

(e)

Concentration (mmolL)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash80

Curr

ent (μA

)

R2 = 098509

R2 = 098728

UA

0 2 4 6 8 10

(f)

Figure 4 DPVs of different concentrations of (a) AA (c) DA and (e) UA on PdNPsrGOGCE in 01MPB (pH 72) calibration plots for (b)AA (d) DA and (f) UA

International Journal of Analytical Chemistry 7

deviation (RSD) of the DPV responses of AA DA and UAwas calculated as 098 208 and 06 respectively re-vealing that the proposed sensor has high reproducibility

Chronoamperometry was used to access the stability ofPdNPsrGOGCE toward 1mMAA 20 μMDA and 05mM

UA in 01MPB for 2000 s at +06V From Figures 7(b)ndash7(d)the current response of these three analytes reached a steadystate in a short time and the changes over a long period werenegligible which suggested that this sensor is suitable forlong-term detection of AA DA and UA

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

075 mM

5 mM

(a)

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

ndash40

ndash450 1 2 3 4 5

Curr

ent (μA

)

Concentration (mmolL)

R2 = 099921

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

13 μM

61 μM

(c)

ndash8

ndash10

ndash12

ndash14

ndash16

ndash18

ndash20

ndash2210 20 30 40 50 60

Curr

ent (μA

)

Concentration (μmolL)

R2 = 099489

DA

(d)

000000

ndash000002

ndash000004

ndash000006

ndash000008

ndash000010

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

01 mM

75 mM

(e)

0

ndash20

ndash40

ndash60

ndash80

ndash1000 1 2 3 4 5 6 7 8

Curr

ent (μA

)

Concentration (mmolL)

R2 = 098595

R2 = 098619

UA

(f )

Figure 5 DPVs of different concentrations of (a) AA in the presence of 20 μMDA and 05mM UA (c) DA in the presence of 15mM AAand 05mM UA and (e) UA in the presence of 075mM AA and 10 μM DA Calibration plots for (b) AA (d) DA and (f) UA

8 International Journal of Analytical Chemistry

36 Study of Anti-Interference Ability Lastly to evaluate theanti-interference ability of PdNPsrGOGCE the interfer-ence of Na+ (d) Clminus (e) Mg2+ (f) SO42minus (g) and glucose (h)with 100-fold concentration in the detection of 1mM AA(a) 50 μM DA (b) and 01mM UA (c) in 01MPB wasconducted by chronoamperometry at a constant potential of+06V for 800 s As shown in Figure 8 with the addition ofAA DA and UA the current signal of PdNPsrGOGCEincreased rapidly with response times of 5 s 5 s and 3 srespectively and the interferents did not produce obvious

effects on the current signal of AA DA and UA As a resultthis proposed sensor was of excellent anti-interferenceability and practical application value

37 Real Samples Detection In order to demonstrate theapplicability of the proposedmethod different concentrations ofAA DA and UA are doped into the human serum samples bythe standard addition method 1e DPV experimental resultsare shown in Table S11e recoveries of the spiked samples were

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

Delt

a I (F

-R) (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

025 mM

35 mM 01 mM

14 mM

3 μM

42 μM

(a)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

00 05 10 15 20 25 30 35 40Concentration (mmolL)

AA

Curr

ent (μA

)

R2 = 099187

(b)

Concentration (μmolL)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

0 10 20 30 40 50

Curr

ent (μA

)

R2 = 099598

R2 = 099248

DA

(c)

Concentration (mmolL)00 02 04 06 08 10 12 14 16

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

Curr

ent (μA

)

R2 = 098765

UA

(d)

Figure 6 DPV curves of different concentrations of AA DA and UA (a) calibration plots for (b) AA (c) DA and (d) UA

Table 1 Analytical parameters for individual selective and simultaneous detection of AA DA and UA at PdNPsrGOGCE

Analytical parameter Analyte Individual detection Selective detection Simultaneous detection

Linear range (μM)AA 300ndash7000 8000ndash20000 750ndash5000 500ndash3500DA 3ndash50 60ndash170 13ndash61 3ndash15 15ndash42UA 50ndash1000 1500ndash4500 500ndash4000 4500ndash7500 300ndash1400

Sensitivity (μA middot μMminus1 middot cmminus2)AA 0069 0028 0107 0079DA 4300 1443 3254 10893 6083UA 0416 0118 0194 0049 0481

International Journal of Analytical Chemistry 9

Table 2 Comparison of different electrodes in the simultaneous detection of AA DA and UA

Electrode pHLinear range (μM)

Sensitivity (μA middot μMminus1 middot cmminus2) RefAA DA UA

MgO nanobeltsGCE 50 25ndash15 25ndash1500198 0028

0125ndash757908

05ndash3 5ndash30283 0962 [30]

SnO2chitosanGCE 70 20ndash2200127

01ndash182773

1ndash1002391 [45]

3DGHa-AuNPsbGCE 70 10ndash7000217

02ndash303897

1ndash601703 [46]

AuNPsbMoS2 nanosheetsGCE 40 12ndash8000481

10ndash3000979

8ndash9000465 [47]

Pd3Pt1cPDDAd-rGOGCE 74 40ndash12000359

4ndash2000639

4ndash4000498 [48]

CBeGCE 70 191ndash3780214

0599ndash1181570

101ndash140680 [49]

PtNP-AuSnfCFPg 70 200ndash120000004

05ndash1000017

25ndash50000003 [50]

PdNPsrGOGCE 72 500ndash35000079

3ndash15 15ndash4210893 6083

300ndash14000481 1is work

a three dimensional graphene hydrogel b gold nanoparticles c Pd-Pt bimetallic nanoparticles d poly(diallyldimethylammonium chloride) e nano-structured carbon black f Pt nanoparticle-modified nanoporous AuSn g Ni-buffered flexible carbon fiber paper

80

70

60

50

40

30

20

10

01 2 3 4 5 6

Electrode number

Curr

ent (μA

)

AADAUA

(a)

0 500 1000 1500 2000Elapsed time (s)

0000007

0000006

0000005

0000004

0000003

0000002

0000001

0000000

Curr

ent (

A)

AA

(b)

0 500 1000 1500 2000Elapsed time (s)

00000035

00000030

00000025

00000020

00000015

00000010

00000005

00000000

Curr

ent (

A)

DA

(c)

0 500 1000 1500 2000Elapsed time (s)

000008

000007

000006

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

UA

(d)

Figure 7 (a) Reproducibility of CQDs-rGOGCE stability of (b) 1mM AA (c) 20 μM DA and (d) 05mM UA

10 International Journal of Analytical Chemistry

detected within the range of 966ndash1085 suggesting theapplicability of the prepared sensor to real samples

4 Conclusions

In summary this paper has proposed a novel approach forthe synthesis of PdNPsrGO nanocomposite by two-step CVelectrodeposition the increased surface area of as-preparedmaterial has contributed to improve the contact probabilitybetween electrode surface and analytes thus elevating thecatalytic activity of the modified electrode which wasconfirmed using CV and EIS After optimizing the experi-mental conditions the sensor showed excellent separationability and fast response for AA DA and UA and has stronganti-interference ability for some common interferingsubstances Besides good reproducibility and stability werealso obtained by this sensor 1e above results revealed thatPdNPsrGOGCE can be a good candidate in the sensingapplication of AA DA and UA in the future

Data Availability

1e generated or analyzed data used to support the findingsof this study are included within the article

Conflicts of Interest

1e authors declare that they have no conflicts of interest

Acknowledgments

1is study was financially supported by the National KeyRampD Program of China (no 2019YFC1709000) NationalNatural Science Foundation of China (NSFC) (nos81973944 and 81503636) National SampT Major Project (no2018ZX09201011) and Youth Talent Promotion Project ofthe China Association for Science and Technology (no 2019-2021ZGZJXH-QNRC001)

Supplementary Materials

Figure S1 EDS characterization of PdNPsrGO nano-composites Figure S2 CV characterization of bare GCE (a)rGOGCE (b) and PdNPsrGOGCE (c) in 20mM potas-sium ferricyanide solution containing 01M KCl Table S1detection of AA DA and UA in real samples (n 3)(Supplementary Materials)

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

Curr

ent (

A)

0 200 400 600 800Time (s)

5 s

180 200 220 240 260 280 300

000005000004000003000002000001000000

Time (s)

AA

d

a

e f g h

(a)

Curr

ent (

A)

Curr

ent (

A)

0000012

0000010

0000008

0000006

0000004

0000002

0000000

ndash00000020 200 400 600 800

Time (s)

5 s180 200 220 240 260 280 300

000002000000180000016000001400000120000010

000008000006000004000002000000

ndash000002

Time (s)

DA

d

b

e f g h

(b)

Curr

ent (

A)Cu

rren

t (A

)

0 200 400 600 800Time (s)

00000010

00000008

00000006

00000004

00000002

00000000

ndash00000002

3 s

200 220 240 260 280Time (s)

000000100000000800000006000000040000000200000000

ndash00000002

UA

d e f g h

c

(c)

Figure 8 Amperometric responses of 1mM AA (a) 50 μM DA (b) and 01mM UA (c) in the presence of 100-fold concentration ofinterferents

International Journal of Analytical Chemistry 11

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 5: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

ndash0000004

ndash0000006

ndash0000008

ndash0000010

ndash0000012

ndash0000014

ndash0000016

ndash0000018

ndash0000020

ndash0000022

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

pH 64pH 68

pH 72pH 76

(a)

000003

000002

000001

000000

ndash000001

ndash000002

ndash000003

ndash000004

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

pH 64

pH 68

pH 72

pH 76AA DA UA

(b)

Figure 2 (a) DPVs of 075mM AA 30 μM DA and 125mM UA at PdNPsrGOGCE at various pH values (black 64 red 68 blue 72green 76) (b) DPV curves after translation

0602 04ndash04 ndash02 00ndash06Potential (V)

ndash000003

ndash000002

ndash000001

000000

000001

000002

Curr

ent (

A)

250 mVs

50 mVs

AA

(a)

Curr

ent (μA

)

AA

50 100 150 200 250Scan rate (mV)

20

18

16

14

12

R2 = 099406

(b)

ndash000003

ndash000002

ndash000001

000000

000001

000002

Curr

ent (

A)

250 mVs

50 mVs

DA

0602 04ndash04 ndash02 00ndash06Potential (V)

(c)

Curr

ent (μA

)

DA

50 100 150 200 250Scan rate (mV)

R2 = 099504

R2 = 099348

15

10

5

0

ndash5

(d)

Figure 3 Continued

International Journal of Analytical Chemistry 5

ndash000003

ndash000002

ndash000001

000000

000001

000002Cu

rren

t (A

)250 mVs

50 mVs

UA

0602 04ndash04 ndash02 00ndash06Potential (V)

(e)

Curr

ent (μA

)

UA

50 100 150 200 250Scan rate (mV)

13

12

11

10

9

8

7

6

R2 = 099712

(f )

Figure 3 CV voltammograms of AA (a) DA (c) and UA (e) on PdNPsrGOGCE at 50 100 150 200 and 250mVmiddotsminus1 scan ratesrelationship between the peak current of (b) AA (d) DA and (f) UA and the scan rates

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

03 mM

30 mM

AA

(a)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash800 5 10 15 20 25 30

Concentration (mmolL)

Curr

ent (μA

)

R2 = 098613

R2 = 098753

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

ndash0000030

ndash0000035ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

3 μM

170 μM

DA

(c)

0

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

Concentration (μmolL)

Curr

ent (μA

)

R2 = 098578

R2 = 098815

ndash20 0 20 40 60 80 100 120 140 160 180

DA

(d)

Figure 4 Continued

6 International Journal of Analytical Chemistry

As can be seen fromFigure 4 at PdNPsrGOGCE the peakcurrent signals of AA DA and UA were all gradually increasedwith their rising levels and achieve a good linear relationship inthe concentration ranges of 03ndash7mM and 8ndash20mM 3ndash50μMand 60ndash170μM and 005ndash1mM and 15ndash45mM with detec-tion limits of 01mM 1μM and 1667μM (SN 3) respec-tively In addition from Figure 4(a) it is worth noting that withthe increase in AA concentration the peak potential of AAshifts to the right indicating that protons have participated inthe electrode reaction process of AA [32] Meanwhile the peakshape of AA gradually widens which is consistent with previousstudies [33ndash35] that may be related to the excessive concen-tration of AA At low AA levels the local AA on the electrodesurface was rapidly catalyzed and the response was fast At highAA concentrations a large amount of AA was adsorbed on theelectrode surface leading to the reduction of the active sites onthe surface of electrode prolonging the catalytic time of PdNPsrGOGCE for AA thus slowing down the catalytic process andwidening the peak shape [36] 1e oxidation mechanisms ofAA DA and UA may be inferred as follows (1) electrostaticinteraction between positive DA and negative functional groupson PdNPsrGOGCE surface (2) the hydrogen bond interac-tion between the hydroxyl groups of AA DA and UA and theoxygen-containing functional groups on the surface of PdNPsrGOGCE

Figures 5 and 6 exhibit the selective and simultaneousdetection results of AA DA and UA It is worth mentioningthat the selective detection was carried out by changing theconcentrations of target species while keeping the other twosubstances at constant in a mixture of AA DA and UA Ascan be observed there exists three well-separated potentialpeaks corresponding to AA DA and UA either in selectiveor simultaneous detection and the presence of the other twospecies did not produce significant impact on the currentsignal of the target analyte suggesting that PdNPsrGOGCE possesses good separation capacity toward AA DAand UA 1e detailed results are presented in Table 1Compared with individual detection the linear range of AA

DA and UA under the same concentration range and thesensitivity of PdNPsrGOGCE toward these three analytesall produced a negligible change either in selective or si-multaneous detection

In addition it can be observed from Figure 5(a) thatwith the increase in AA concentration in addition to theincreasing AA current the detection currents of DA andUA were also increased which is consistent with previousliteratures [28 29 37ndash41] that can be related to the ad-sorption of DA and UA on the electrode surface [42] 1ehigher concentration of AA on electrode surface contin-uously reacts with the oxidation products of DA and UAresulting in the regeneration of DA and UA thus in-creasing the current [43 44] Moreover from Figures 4(a)5(a) and 6(a) it is worthy to note that the oxidationvoltages of AA in these three experiments were not thesame which may be related to the concentration range ofAA and the interaction between AA and DA and UA[43 44]

As shown in Table 2 although most of previous worksshowed higher sensitivity toward AA and UA than PdNPsrGOGCE from the perspective of sensitivity toward DAand linear range PdNPsrGOGCE still occupies a uniqueadvantage in the simultaneous detection of AA DA andUA

1e above results showed that the developed sensor has agood application value in the detection of AA DA and UA

35 Reproducibility and Stability of the SensorReproducibility and stability are also crucial indicators forthe evaluation of the electrochemical performances of thedeveloped sensor

1e reproducibility of PdNPsrGOGCE was studied byDPV using six sensors that were prepared under the sameconditions to detect 1mM AA 10 μM DA and 25mM UAin 01MPB respectively and the results were exhibited inthe form of histogram (Figure 7(a)) 1e relative standard

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

005 mM

9 mM

UA

(e)

Concentration (mmolL)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash80

Curr

ent (μA

)

R2 = 098509

R2 = 098728

UA

0 2 4 6 8 10

(f)

Figure 4 DPVs of different concentrations of (a) AA (c) DA and (e) UA on PdNPsrGOGCE in 01MPB (pH 72) calibration plots for (b)AA (d) DA and (f) UA

International Journal of Analytical Chemistry 7

deviation (RSD) of the DPV responses of AA DA and UAwas calculated as 098 208 and 06 respectively re-vealing that the proposed sensor has high reproducibility

Chronoamperometry was used to access the stability ofPdNPsrGOGCE toward 1mMAA 20 μMDA and 05mM

UA in 01MPB for 2000 s at +06V From Figures 7(b)ndash7(d)the current response of these three analytes reached a steadystate in a short time and the changes over a long period werenegligible which suggested that this sensor is suitable forlong-term detection of AA DA and UA

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

075 mM

5 mM

(a)

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

ndash40

ndash450 1 2 3 4 5

Curr

ent (μA

)

Concentration (mmolL)

R2 = 099921

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

13 μM

61 μM

(c)

ndash8

ndash10

ndash12

ndash14

ndash16

ndash18

ndash20

ndash2210 20 30 40 50 60

Curr

ent (μA

)

Concentration (μmolL)

R2 = 099489

DA

(d)

000000

ndash000002

ndash000004

ndash000006

ndash000008

ndash000010

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

01 mM

75 mM

(e)

0

ndash20

ndash40

ndash60

ndash80

ndash1000 1 2 3 4 5 6 7 8

Curr

ent (μA

)

Concentration (mmolL)

R2 = 098595

R2 = 098619

UA

(f )

Figure 5 DPVs of different concentrations of (a) AA in the presence of 20 μMDA and 05mM UA (c) DA in the presence of 15mM AAand 05mM UA and (e) UA in the presence of 075mM AA and 10 μM DA Calibration plots for (b) AA (d) DA and (f) UA

8 International Journal of Analytical Chemistry

36 Study of Anti-Interference Ability Lastly to evaluate theanti-interference ability of PdNPsrGOGCE the interfer-ence of Na+ (d) Clminus (e) Mg2+ (f) SO42minus (g) and glucose (h)with 100-fold concentration in the detection of 1mM AA(a) 50 μM DA (b) and 01mM UA (c) in 01MPB wasconducted by chronoamperometry at a constant potential of+06V for 800 s As shown in Figure 8 with the addition ofAA DA and UA the current signal of PdNPsrGOGCEincreased rapidly with response times of 5 s 5 s and 3 srespectively and the interferents did not produce obvious

effects on the current signal of AA DA and UA As a resultthis proposed sensor was of excellent anti-interferenceability and practical application value

37 Real Samples Detection In order to demonstrate theapplicability of the proposedmethod different concentrations ofAA DA and UA are doped into the human serum samples bythe standard addition method 1e DPV experimental resultsare shown in Table S11e recoveries of the spiked samples were

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

Delt

a I (F

-R) (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

025 mM

35 mM 01 mM

14 mM

3 μM

42 μM

(a)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

00 05 10 15 20 25 30 35 40Concentration (mmolL)

AA

Curr

ent (μA

)

R2 = 099187

(b)

Concentration (μmolL)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

0 10 20 30 40 50

Curr

ent (μA

)

R2 = 099598

R2 = 099248

DA

(c)

Concentration (mmolL)00 02 04 06 08 10 12 14 16

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

Curr

ent (μA

)

R2 = 098765

UA

(d)

Figure 6 DPV curves of different concentrations of AA DA and UA (a) calibration plots for (b) AA (c) DA and (d) UA

Table 1 Analytical parameters for individual selective and simultaneous detection of AA DA and UA at PdNPsrGOGCE

Analytical parameter Analyte Individual detection Selective detection Simultaneous detection

Linear range (μM)AA 300ndash7000 8000ndash20000 750ndash5000 500ndash3500DA 3ndash50 60ndash170 13ndash61 3ndash15 15ndash42UA 50ndash1000 1500ndash4500 500ndash4000 4500ndash7500 300ndash1400

Sensitivity (μA middot μMminus1 middot cmminus2)AA 0069 0028 0107 0079DA 4300 1443 3254 10893 6083UA 0416 0118 0194 0049 0481

International Journal of Analytical Chemistry 9

Table 2 Comparison of different electrodes in the simultaneous detection of AA DA and UA

Electrode pHLinear range (μM)

Sensitivity (μA middot μMminus1 middot cmminus2) RefAA DA UA

MgO nanobeltsGCE 50 25ndash15 25ndash1500198 0028

0125ndash757908

05ndash3 5ndash30283 0962 [30]

SnO2chitosanGCE 70 20ndash2200127

01ndash182773

1ndash1002391 [45]

3DGHa-AuNPsbGCE 70 10ndash7000217

02ndash303897

1ndash601703 [46]

AuNPsbMoS2 nanosheetsGCE 40 12ndash8000481

10ndash3000979

8ndash9000465 [47]

Pd3Pt1cPDDAd-rGOGCE 74 40ndash12000359

4ndash2000639

4ndash4000498 [48]

CBeGCE 70 191ndash3780214

0599ndash1181570

101ndash140680 [49]

PtNP-AuSnfCFPg 70 200ndash120000004

05ndash1000017

25ndash50000003 [50]

PdNPsrGOGCE 72 500ndash35000079

3ndash15 15ndash4210893 6083

300ndash14000481 1is work

a three dimensional graphene hydrogel b gold nanoparticles c Pd-Pt bimetallic nanoparticles d poly(diallyldimethylammonium chloride) e nano-structured carbon black f Pt nanoparticle-modified nanoporous AuSn g Ni-buffered flexible carbon fiber paper

80

70

60

50

40

30

20

10

01 2 3 4 5 6

Electrode number

Curr

ent (μA

)

AADAUA

(a)

0 500 1000 1500 2000Elapsed time (s)

0000007

0000006

0000005

0000004

0000003

0000002

0000001

0000000

Curr

ent (

A)

AA

(b)

0 500 1000 1500 2000Elapsed time (s)

00000035

00000030

00000025

00000020

00000015

00000010

00000005

00000000

Curr

ent (

A)

DA

(c)

0 500 1000 1500 2000Elapsed time (s)

000008

000007

000006

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

UA

(d)

Figure 7 (a) Reproducibility of CQDs-rGOGCE stability of (b) 1mM AA (c) 20 μM DA and (d) 05mM UA

10 International Journal of Analytical Chemistry

detected within the range of 966ndash1085 suggesting theapplicability of the prepared sensor to real samples

4 Conclusions

In summary this paper has proposed a novel approach forthe synthesis of PdNPsrGO nanocomposite by two-step CVelectrodeposition the increased surface area of as-preparedmaterial has contributed to improve the contact probabilitybetween electrode surface and analytes thus elevating thecatalytic activity of the modified electrode which wasconfirmed using CV and EIS After optimizing the experi-mental conditions the sensor showed excellent separationability and fast response for AA DA and UA and has stronganti-interference ability for some common interferingsubstances Besides good reproducibility and stability werealso obtained by this sensor 1e above results revealed thatPdNPsrGOGCE can be a good candidate in the sensingapplication of AA DA and UA in the future

Data Availability

1e generated or analyzed data used to support the findingsof this study are included within the article

Conflicts of Interest

1e authors declare that they have no conflicts of interest

Acknowledgments

1is study was financially supported by the National KeyRampD Program of China (no 2019YFC1709000) NationalNatural Science Foundation of China (NSFC) (nos81973944 and 81503636) National SampT Major Project (no2018ZX09201011) and Youth Talent Promotion Project ofthe China Association for Science and Technology (no 2019-2021ZGZJXH-QNRC001)

Supplementary Materials

Figure S1 EDS characterization of PdNPsrGO nano-composites Figure S2 CV characterization of bare GCE (a)rGOGCE (b) and PdNPsrGOGCE (c) in 20mM potas-sium ferricyanide solution containing 01M KCl Table S1detection of AA DA and UA in real samples (n 3)(Supplementary Materials)

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

Curr

ent (

A)

0 200 400 600 800Time (s)

5 s

180 200 220 240 260 280 300

000005000004000003000002000001000000

Time (s)

AA

d

a

e f g h

(a)

Curr

ent (

A)

Curr

ent (

A)

0000012

0000010

0000008

0000006

0000004

0000002

0000000

ndash00000020 200 400 600 800

Time (s)

5 s180 200 220 240 260 280 300

000002000000180000016000001400000120000010

000008000006000004000002000000

ndash000002

Time (s)

DA

d

b

e f g h

(b)

Curr

ent (

A)Cu

rren

t (A

)

0 200 400 600 800Time (s)

00000010

00000008

00000006

00000004

00000002

00000000

ndash00000002

3 s

200 220 240 260 280Time (s)

000000100000000800000006000000040000000200000000

ndash00000002

UA

d e f g h

c

(c)

Figure 8 Amperometric responses of 1mM AA (a) 50 μM DA (b) and 01mM UA (c) in the presence of 100-fold concentration ofinterferents

International Journal of Analytical Chemistry 11

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 6: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

ndash000003

ndash000002

ndash000001

000000

000001

000002Cu

rren

t (A

)250 mVs

50 mVs

UA

0602 04ndash04 ndash02 00ndash06Potential (V)

(e)

Curr

ent (μA

)

UA

50 100 150 200 250Scan rate (mV)

13

12

11

10

9

8

7

6

R2 = 099712

(f )

Figure 3 CV voltammograms of AA (a) DA (c) and UA (e) on PdNPsrGOGCE at 50 100 150 200 and 250mVmiddotsminus1 scan ratesrelationship between the peak current of (b) AA (d) DA and (f) UA and the scan rates

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

03 mM

30 mM

AA

(a)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash800 5 10 15 20 25 30

Concentration (mmolL)

Curr

ent (μA

)

R2 = 098613

R2 = 098753

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

ndash0000030

ndash0000035ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

3 μM

170 μM

DA

(c)

0

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

Concentration (μmolL)

Curr

ent (μA

)

R2 = 098578

R2 = 098815

ndash20 0 20 40 60 80 100 120 140 160 180

DA

(d)

Figure 4 Continued

6 International Journal of Analytical Chemistry

As can be seen fromFigure 4 at PdNPsrGOGCE the peakcurrent signals of AA DA and UA were all gradually increasedwith their rising levels and achieve a good linear relationship inthe concentration ranges of 03ndash7mM and 8ndash20mM 3ndash50μMand 60ndash170μM and 005ndash1mM and 15ndash45mM with detec-tion limits of 01mM 1μM and 1667μM (SN 3) respec-tively In addition from Figure 4(a) it is worth noting that withthe increase in AA concentration the peak potential of AAshifts to the right indicating that protons have participated inthe electrode reaction process of AA [32] Meanwhile the peakshape of AA gradually widens which is consistent with previousstudies [33ndash35] that may be related to the excessive concen-tration of AA At low AA levels the local AA on the electrodesurface was rapidly catalyzed and the response was fast At highAA concentrations a large amount of AA was adsorbed on theelectrode surface leading to the reduction of the active sites onthe surface of electrode prolonging the catalytic time of PdNPsrGOGCE for AA thus slowing down the catalytic process andwidening the peak shape [36] 1e oxidation mechanisms ofAA DA and UA may be inferred as follows (1) electrostaticinteraction between positive DA and negative functional groupson PdNPsrGOGCE surface (2) the hydrogen bond interac-tion between the hydroxyl groups of AA DA and UA and theoxygen-containing functional groups on the surface of PdNPsrGOGCE

Figures 5 and 6 exhibit the selective and simultaneousdetection results of AA DA and UA It is worth mentioningthat the selective detection was carried out by changing theconcentrations of target species while keeping the other twosubstances at constant in a mixture of AA DA and UA Ascan be observed there exists three well-separated potentialpeaks corresponding to AA DA and UA either in selectiveor simultaneous detection and the presence of the other twospecies did not produce significant impact on the currentsignal of the target analyte suggesting that PdNPsrGOGCE possesses good separation capacity toward AA DAand UA 1e detailed results are presented in Table 1Compared with individual detection the linear range of AA

DA and UA under the same concentration range and thesensitivity of PdNPsrGOGCE toward these three analytesall produced a negligible change either in selective or si-multaneous detection

In addition it can be observed from Figure 5(a) thatwith the increase in AA concentration in addition to theincreasing AA current the detection currents of DA andUA were also increased which is consistent with previousliteratures [28 29 37ndash41] that can be related to the ad-sorption of DA and UA on the electrode surface [42] 1ehigher concentration of AA on electrode surface contin-uously reacts with the oxidation products of DA and UAresulting in the regeneration of DA and UA thus in-creasing the current [43 44] Moreover from Figures 4(a)5(a) and 6(a) it is worthy to note that the oxidationvoltages of AA in these three experiments were not thesame which may be related to the concentration range ofAA and the interaction between AA and DA and UA[43 44]

As shown in Table 2 although most of previous worksshowed higher sensitivity toward AA and UA than PdNPsrGOGCE from the perspective of sensitivity toward DAand linear range PdNPsrGOGCE still occupies a uniqueadvantage in the simultaneous detection of AA DA andUA

1e above results showed that the developed sensor has agood application value in the detection of AA DA and UA

35 Reproducibility and Stability of the SensorReproducibility and stability are also crucial indicators forthe evaluation of the electrochemical performances of thedeveloped sensor

1e reproducibility of PdNPsrGOGCE was studied byDPV using six sensors that were prepared under the sameconditions to detect 1mM AA 10 μM DA and 25mM UAin 01MPB respectively and the results were exhibited inthe form of histogram (Figure 7(a)) 1e relative standard

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

005 mM

9 mM

UA

(e)

Concentration (mmolL)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash80

Curr

ent (μA

)

R2 = 098509

R2 = 098728

UA

0 2 4 6 8 10

(f)

Figure 4 DPVs of different concentrations of (a) AA (c) DA and (e) UA on PdNPsrGOGCE in 01MPB (pH 72) calibration plots for (b)AA (d) DA and (f) UA

International Journal of Analytical Chemistry 7

deviation (RSD) of the DPV responses of AA DA and UAwas calculated as 098 208 and 06 respectively re-vealing that the proposed sensor has high reproducibility

Chronoamperometry was used to access the stability ofPdNPsrGOGCE toward 1mMAA 20 μMDA and 05mM

UA in 01MPB for 2000 s at +06V From Figures 7(b)ndash7(d)the current response of these three analytes reached a steadystate in a short time and the changes over a long period werenegligible which suggested that this sensor is suitable forlong-term detection of AA DA and UA

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

075 mM

5 mM

(a)

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

ndash40

ndash450 1 2 3 4 5

Curr

ent (μA

)

Concentration (mmolL)

R2 = 099921

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

13 μM

61 μM

(c)

ndash8

ndash10

ndash12

ndash14

ndash16

ndash18

ndash20

ndash2210 20 30 40 50 60

Curr

ent (μA

)

Concentration (μmolL)

R2 = 099489

DA

(d)

000000

ndash000002

ndash000004

ndash000006

ndash000008

ndash000010

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

01 mM

75 mM

(e)

0

ndash20

ndash40

ndash60

ndash80

ndash1000 1 2 3 4 5 6 7 8

Curr

ent (μA

)

Concentration (mmolL)

R2 = 098595

R2 = 098619

UA

(f )

Figure 5 DPVs of different concentrations of (a) AA in the presence of 20 μMDA and 05mM UA (c) DA in the presence of 15mM AAand 05mM UA and (e) UA in the presence of 075mM AA and 10 μM DA Calibration plots for (b) AA (d) DA and (f) UA

8 International Journal of Analytical Chemistry

36 Study of Anti-Interference Ability Lastly to evaluate theanti-interference ability of PdNPsrGOGCE the interfer-ence of Na+ (d) Clminus (e) Mg2+ (f) SO42minus (g) and glucose (h)with 100-fold concentration in the detection of 1mM AA(a) 50 μM DA (b) and 01mM UA (c) in 01MPB wasconducted by chronoamperometry at a constant potential of+06V for 800 s As shown in Figure 8 with the addition ofAA DA and UA the current signal of PdNPsrGOGCEincreased rapidly with response times of 5 s 5 s and 3 srespectively and the interferents did not produce obvious

effects on the current signal of AA DA and UA As a resultthis proposed sensor was of excellent anti-interferenceability and practical application value

37 Real Samples Detection In order to demonstrate theapplicability of the proposedmethod different concentrations ofAA DA and UA are doped into the human serum samples bythe standard addition method 1e DPV experimental resultsare shown in Table S11e recoveries of the spiked samples were

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

Delt

a I (F

-R) (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

025 mM

35 mM 01 mM

14 mM

3 μM

42 μM

(a)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

00 05 10 15 20 25 30 35 40Concentration (mmolL)

AA

Curr

ent (μA

)

R2 = 099187

(b)

Concentration (μmolL)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

0 10 20 30 40 50

Curr

ent (μA

)

R2 = 099598

R2 = 099248

DA

(c)

Concentration (mmolL)00 02 04 06 08 10 12 14 16

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

Curr

ent (μA

)

R2 = 098765

UA

(d)

Figure 6 DPV curves of different concentrations of AA DA and UA (a) calibration plots for (b) AA (c) DA and (d) UA

Table 1 Analytical parameters for individual selective and simultaneous detection of AA DA and UA at PdNPsrGOGCE

Analytical parameter Analyte Individual detection Selective detection Simultaneous detection

Linear range (μM)AA 300ndash7000 8000ndash20000 750ndash5000 500ndash3500DA 3ndash50 60ndash170 13ndash61 3ndash15 15ndash42UA 50ndash1000 1500ndash4500 500ndash4000 4500ndash7500 300ndash1400

Sensitivity (μA middot μMminus1 middot cmminus2)AA 0069 0028 0107 0079DA 4300 1443 3254 10893 6083UA 0416 0118 0194 0049 0481

International Journal of Analytical Chemistry 9

Table 2 Comparison of different electrodes in the simultaneous detection of AA DA and UA

Electrode pHLinear range (μM)

Sensitivity (μA middot μMminus1 middot cmminus2) RefAA DA UA

MgO nanobeltsGCE 50 25ndash15 25ndash1500198 0028

0125ndash757908

05ndash3 5ndash30283 0962 [30]

SnO2chitosanGCE 70 20ndash2200127

01ndash182773

1ndash1002391 [45]

3DGHa-AuNPsbGCE 70 10ndash7000217

02ndash303897

1ndash601703 [46]

AuNPsbMoS2 nanosheetsGCE 40 12ndash8000481

10ndash3000979

8ndash9000465 [47]

Pd3Pt1cPDDAd-rGOGCE 74 40ndash12000359

4ndash2000639

4ndash4000498 [48]

CBeGCE 70 191ndash3780214

0599ndash1181570

101ndash140680 [49]

PtNP-AuSnfCFPg 70 200ndash120000004

05ndash1000017

25ndash50000003 [50]

PdNPsrGOGCE 72 500ndash35000079

3ndash15 15ndash4210893 6083

300ndash14000481 1is work

a three dimensional graphene hydrogel b gold nanoparticles c Pd-Pt bimetallic nanoparticles d poly(diallyldimethylammonium chloride) e nano-structured carbon black f Pt nanoparticle-modified nanoporous AuSn g Ni-buffered flexible carbon fiber paper

80

70

60

50

40

30

20

10

01 2 3 4 5 6

Electrode number

Curr

ent (μA

)

AADAUA

(a)

0 500 1000 1500 2000Elapsed time (s)

0000007

0000006

0000005

0000004

0000003

0000002

0000001

0000000

Curr

ent (

A)

AA

(b)

0 500 1000 1500 2000Elapsed time (s)

00000035

00000030

00000025

00000020

00000015

00000010

00000005

00000000

Curr

ent (

A)

DA

(c)

0 500 1000 1500 2000Elapsed time (s)

000008

000007

000006

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

UA

(d)

Figure 7 (a) Reproducibility of CQDs-rGOGCE stability of (b) 1mM AA (c) 20 μM DA and (d) 05mM UA

10 International Journal of Analytical Chemistry

detected within the range of 966ndash1085 suggesting theapplicability of the prepared sensor to real samples

4 Conclusions

In summary this paper has proposed a novel approach forthe synthesis of PdNPsrGO nanocomposite by two-step CVelectrodeposition the increased surface area of as-preparedmaterial has contributed to improve the contact probabilitybetween electrode surface and analytes thus elevating thecatalytic activity of the modified electrode which wasconfirmed using CV and EIS After optimizing the experi-mental conditions the sensor showed excellent separationability and fast response for AA DA and UA and has stronganti-interference ability for some common interferingsubstances Besides good reproducibility and stability werealso obtained by this sensor 1e above results revealed thatPdNPsrGOGCE can be a good candidate in the sensingapplication of AA DA and UA in the future

Data Availability

1e generated or analyzed data used to support the findingsof this study are included within the article

Conflicts of Interest

1e authors declare that they have no conflicts of interest

Acknowledgments

1is study was financially supported by the National KeyRampD Program of China (no 2019YFC1709000) NationalNatural Science Foundation of China (NSFC) (nos81973944 and 81503636) National SampT Major Project (no2018ZX09201011) and Youth Talent Promotion Project ofthe China Association for Science and Technology (no 2019-2021ZGZJXH-QNRC001)

Supplementary Materials

Figure S1 EDS characterization of PdNPsrGO nano-composites Figure S2 CV characterization of bare GCE (a)rGOGCE (b) and PdNPsrGOGCE (c) in 20mM potas-sium ferricyanide solution containing 01M KCl Table S1detection of AA DA and UA in real samples (n 3)(Supplementary Materials)

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

Curr

ent (

A)

0 200 400 600 800Time (s)

5 s

180 200 220 240 260 280 300

000005000004000003000002000001000000

Time (s)

AA

d

a

e f g h

(a)

Curr

ent (

A)

Curr

ent (

A)

0000012

0000010

0000008

0000006

0000004

0000002

0000000

ndash00000020 200 400 600 800

Time (s)

5 s180 200 220 240 260 280 300

000002000000180000016000001400000120000010

000008000006000004000002000000

ndash000002

Time (s)

DA

d

b

e f g h

(b)

Curr

ent (

A)Cu

rren

t (A

)

0 200 400 600 800Time (s)

00000010

00000008

00000006

00000004

00000002

00000000

ndash00000002

3 s

200 220 240 260 280Time (s)

000000100000000800000006000000040000000200000000

ndash00000002

UA

d e f g h

c

(c)

Figure 8 Amperometric responses of 1mM AA (a) 50 μM DA (b) and 01mM UA (c) in the presence of 100-fold concentration ofinterferents

International Journal of Analytical Chemistry 11

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 7: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

As can be seen fromFigure 4 at PdNPsrGOGCE the peakcurrent signals of AA DA and UA were all gradually increasedwith their rising levels and achieve a good linear relationship inthe concentration ranges of 03ndash7mM and 8ndash20mM 3ndash50μMand 60ndash170μM and 005ndash1mM and 15ndash45mM with detec-tion limits of 01mM 1μM and 1667μM (SN 3) respec-tively In addition from Figure 4(a) it is worth noting that withthe increase in AA concentration the peak potential of AAshifts to the right indicating that protons have participated inthe electrode reaction process of AA [32] Meanwhile the peakshape of AA gradually widens which is consistent with previousstudies [33ndash35] that may be related to the excessive concen-tration of AA At low AA levels the local AA on the electrodesurface was rapidly catalyzed and the response was fast At highAA concentrations a large amount of AA was adsorbed on theelectrode surface leading to the reduction of the active sites onthe surface of electrode prolonging the catalytic time of PdNPsrGOGCE for AA thus slowing down the catalytic process andwidening the peak shape [36] 1e oxidation mechanisms ofAA DA and UA may be inferred as follows (1) electrostaticinteraction between positive DA and negative functional groupson PdNPsrGOGCE surface (2) the hydrogen bond interac-tion between the hydroxyl groups of AA DA and UA and theoxygen-containing functional groups on the surface of PdNPsrGOGCE

Figures 5 and 6 exhibit the selective and simultaneousdetection results of AA DA and UA It is worth mentioningthat the selective detection was carried out by changing theconcentrations of target species while keeping the other twosubstances at constant in a mixture of AA DA and UA Ascan be observed there exists three well-separated potentialpeaks corresponding to AA DA and UA either in selectiveor simultaneous detection and the presence of the other twospecies did not produce significant impact on the currentsignal of the target analyte suggesting that PdNPsrGOGCE possesses good separation capacity toward AA DAand UA 1e detailed results are presented in Table 1Compared with individual detection the linear range of AA

DA and UA under the same concentration range and thesensitivity of PdNPsrGOGCE toward these three analytesall produced a negligible change either in selective or si-multaneous detection

In addition it can be observed from Figure 5(a) thatwith the increase in AA concentration in addition to theincreasing AA current the detection currents of DA andUA were also increased which is consistent with previousliteratures [28 29 37ndash41] that can be related to the ad-sorption of DA and UA on the electrode surface [42] 1ehigher concentration of AA on electrode surface contin-uously reacts with the oxidation products of DA and UAresulting in the regeneration of DA and UA thus in-creasing the current [43 44] Moreover from Figures 4(a)5(a) and 6(a) it is worthy to note that the oxidationvoltages of AA in these three experiments were not thesame which may be related to the concentration range ofAA and the interaction between AA and DA and UA[43 44]

As shown in Table 2 although most of previous worksshowed higher sensitivity toward AA and UA than PdNPsrGOGCE from the perspective of sensitivity toward DAand linear range PdNPsrGOGCE still occupies a uniqueadvantage in the simultaneous detection of AA DA andUA

1e above results showed that the developed sensor has agood application value in the detection of AA DA and UA

35 Reproducibility and Stability of the SensorReproducibility and stability are also crucial indicators forthe evaluation of the electrochemical performances of thedeveloped sensor

1e reproducibility of PdNPsrGOGCE was studied byDPV using six sensors that were prepared under the sameconditions to detect 1mM AA 10 μM DA and 25mM UAin 01MPB respectively and the results were exhibited inthe form of histogram (Figure 7(a)) 1e relative standard

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

ndash000008ndash01 00 01 02 03 04 05 06

Potential (V)

Curr

ent (

A)

005 mM

9 mM

UA

(e)

Concentration (mmolL)

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

ndash80

Curr

ent (μA

)

R2 = 098509

R2 = 098728

UA

0 2 4 6 8 10

(f)

Figure 4 DPVs of different concentrations of (a) AA (c) DA and (e) UA on PdNPsrGOGCE in 01MPB (pH 72) calibration plots for (b)AA (d) DA and (f) UA

International Journal of Analytical Chemistry 7

deviation (RSD) of the DPV responses of AA DA and UAwas calculated as 098 208 and 06 respectively re-vealing that the proposed sensor has high reproducibility

Chronoamperometry was used to access the stability ofPdNPsrGOGCE toward 1mMAA 20 μMDA and 05mM

UA in 01MPB for 2000 s at +06V From Figures 7(b)ndash7(d)the current response of these three analytes reached a steadystate in a short time and the changes over a long period werenegligible which suggested that this sensor is suitable forlong-term detection of AA DA and UA

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

075 mM

5 mM

(a)

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

ndash40

ndash450 1 2 3 4 5

Curr

ent (μA

)

Concentration (mmolL)

R2 = 099921

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

13 μM

61 μM

(c)

ndash8

ndash10

ndash12

ndash14

ndash16

ndash18

ndash20

ndash2210 20 30 40 50 60

Curr

ent (μA

)

Concentration (μmolL)

R2 = 099489

DA

(d)

000000

ndash000002

ndash000004

ndash000006

ndash000008

ndash000010

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

01 mM

75 mM

(e)

0

ndash20

ndash40

ndash60

ndash80

ndash1000 1 2 3 4 5 6 7 8

Curr

ent (μA

)

Concentration (mmolL)

R2 = 098595

R2 = 098619

UA

(f )

Figure 5 DPVs of different concentrations of (a) AA in the presence of 20 μMDA and 05mM UA (c) DA in the presence of 15mM AAand 05mM UA and (e) UA in the presence of 075mM AA and 10 μM DA Calibration plots for (b) AA (d) DA and (f) UA

8 International Journal of Analytical Chemistry

36 Study of Anti-Interference Ability Lastly to evaluate theanti-interference ability of PdNPsrGOGCE the interfer-ence of Na+ (d) Clminus (e) Mg2+ (f) SO42minus (g) and glucose (h)with 100-fold concentration in the detection of 1mM AA(a) 50 μM DA (b) and 01mM UA (c) in 01MPB wasconducted by chronoamperometry at a constant potential of+06V for 800 s As shown in Figure 8 with the addition ofAA DA and UA the current signal of PdNPsrGOGCEincreased rapidly with response times of 5 s 5 s and 3 srespectively and the interferents did not produce obvious

effects on the current signal of AA DA and UA As a resultthis proposed sensor was of excellent anti-interferenceability and practical application value

37 Real Samples Detection In order to demonstrate theapplicability of the proposedmethod different concentrations ofAA DA and UA are doped into the human serum samples bythe standard addition method 1e DPV experimental resultsare shown in Table S11e recoveries of the spiked samples were

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

Delt

a I (F

-R) (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

025 mM

35 mM 01 mM

14 mM

3 μM

42 μM

(a)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

00 05 10 15 20 25 30 35 40Concentration (mmolL)

AA

Curr

ent (μA

)

R2 = 099187

(b)

Concentration (μmolL)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

0 10 20 30 40 50

Curr

ent (μA

)

R2 = 099598

R2 = 099248

DA

(c)

Concentration (mmolL)00 02 04 06 08 10 12 14 16

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

Curr

ent (μA

)

R2 = 098765

UA

(d)

Figure 6 DPV curves of different concentrations of AA DA and UA (a) calibration plots for (b) AA (c) DA and (d) UA

Table 1 Analytical parameters for individual selective and simultaneous detection of AA DA and UA at PdNPsrGOGCE

Analytical parameter Analyte Individual detection Selective detection Simultaneous detection

Linear range (μM)AA 300ndash7000 8000ndash20000 750ndash5000 500ndash3500DA 3ndash50 60ndash170 13ndash61 3ndash15 15ndash42UA 50ndash1000 1500ndash4500 500ndash4000 4500ndash7500 300ndash1400

Sensitivity (μA middot μMminus1 middot cmminus2)AA 0069 0028 0107 0079DA 4300 1443 3254 10893 6083UA 0416 0118 0194 0049 0481

International Journal of Analytical Chemistry 9

Table 2 Comparison of different electrodes in the simultaneous detection of AA DA and UA

Electrode pHLinear range (μM)

Sensitivity (μA middot μMminus1 middot cmminus2) RefAA DA UA

MgO nanobeltsGCE 50 25ndash15 25ndash1500198 0028

0125ndash757908

05ndash3 5ndash30283 0962 [30]

SnO2chitosanGCE 70 20ndash2200127

01ndash182773

1ndash1002391 [45]

3DGHa-AuNPsbGCE 70 10ndash7000217

02ndash303897

1ndash601703 [46]

AuNPsbMoS2 nanosheetsGCE 40 12ndash8000481

10ndash3000979

8ndash9000465 [47]

Pd3Pt1cPDDAd-rGOGCE 74 40ndash12000359

4ndash2000639

4ndash4000498 [48]

CBeGCE 70 191ndash3780214

0599ndash1181570

101ndash140680 [49]

PtNP-AuSnfCFPg 70 200ndash120000004

05ndash1000017

25ndash50000003 [50]

PdNPsrGOGCE 72 500ndash35000079

3ndash15 15ndash4210893 6083

300ndash14000481 1is work

a three dimensional graphene hydrogel b gold nanoparticles c Pd-Pt bimetallic nanoparticles d poly(diallyldimethylammonium chloride) e nano-structured carbon black f Pt nanoparticle-modified nanoporous AuSn g Ni-buffered flexible carbon fiber paper

80

70

60

50

40

30

20

10

01 2 3 4 5 6

Electrode number

Curr

ent (μA

)

AADAUA

(a)

0 500 1000 1500 2000Elapsed time (s)

0000007

0000006

0000005

0000004

0000003

0000002

0000001

0000000

Curr

ent (

A)

AA

(b)

0 500 1000 1500 2000Elapsed time (s)

00000035

00000030

00000025

00000020

00000015

00000010

00000005

00000000

Curr

ent (

A)

DA

(c)

0 500 1000 1500 2000Elapsed time (s)

000008

000007

000006

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

UA

(d)

Figure 7 (a) Reproducibility of CQDs-rGOGCE stability of (b) 1mM AA (c) 20 μM DA and (d) 05mM UA

10 International Journal of Analytical Chemistry

detected within the range of 966ndash1085 suggesting theapplicability of the prepared sensor to real samples

4 Conclusions

In summary this paper has proposed a novel approach forthe synthesis of PdNPsrGO nanocomposite by two-step CVelectrodeposition the increased surface area of as-preparedmaterial has contributed to improve the contact probabilitybetween electrode surface and analytes thus elevating thecatalytic activity of the modified electrode which wasconfirmed using CV and EIS After optimizing the experi-mental conditions the sensor showed excellent separationability and fast response for AA DA and UA and has stronganti-interference ability for some common interferingsubstances Besides good reproducibility and stability werealso obtained by this sensor 1e above results revealed thatPdNPsrGOGCE can be a good candidate in the sensingapplication of AA DA and UA in the future

Data Availability

1e generated or analyzed data used to support the findingsof this study are included within the article

Conflicts of Interest

1e authors declare that they have no conflicts of interest

Acknowledgments

1is study was financially supported by the National KeyRampD Program of China (no 2019YFC1709000) NationalNatural Science Foundation of China (NSFC) (nos81973944 and 81503636) National SampT Major Project (no2018ZX09201011) and Youth Talent Promotion Project ofthe China Association for Science and Technology (no 2019-2021ZGZJXH-QNRC001)

Supplementary Materials

Figure S1 EDS characterization of PdNPsrGO nano-composites Figure S2 CV characterization of bare GCE (a)rGOGCE (b) and PdNPsrGOGCE (c) in 20mM potas-sium ferricyanide solution containing 01M KCl Table S1detection of AA DA and UA in real samples (n 3)(Supplementary Materials)

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

Curr

ent (

A)

0 200 400 600 800Time (s)

5 s

180 200 220 240 260 280 300

000005000004000003000002000001000000

Time (s)

AA

d

a

e f g h

(a)

Curr

ent (

A)

Curr

ent (

A)

0000012

0000010

0000008

0000006

0000004

0000002

0000000

ndash00000020 200 400 600 800

Time (s)

5 s180 200 220 240 260 280 300

000002000000180000016000001400000120000010

000008000006000004000002000000

ndash000002

Time (s)

DA

d

b

e f g h

(b)

Curr

ent (

A)Cu

rren

t (A

)

0 200 400 600 800Time (s)

00000010

00000008

00000006

00000004

00000002

00000000

ndash00000002

3 s

200 220 240 260 280Time (s)

000000100000000800000006000000040000000200000000

ndash00000002

UA

d e f g h

c

(c)

Figure 8 Amperometric responses of 1mM AA (a) 50 μM DA (b) and 01mM UA (c) in the presence of 100-fold concentration ofinterferents

International Journal of Analytical Chemistry 11

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 8: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

deviation (RSD) of the DPV responses of AA DA and UAwas calculated as 098 208 and 06 respectively re-vealing that the proposed sensor has high reproducibility

Chronoamperometry was used to access the stability ofPdNPsrGOGCE toward 1mMAA 20 μMDA and 05mM

UA in 01MPB for 2000 s at +06V From Figures 7(b)ndash7(d)the current response of these three analytes reached a steadystate in a short time and the changes over a long period werenegligible which suggested that this sensor is suitable forlong-term detection of AA DA and UA

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

075 mM

5 mM

(a)

ndash10

ndash15

ndash20

ndash25

ndash30

ndash35

ndash40

ndash450 1 2 3 4 5

Curr

ent (μA

)

Concentration (mmolL)

R2 = 099921

AA

(b)

0000000

ndash0000005

ndash0000010

ndash0000015

ndash0000020

ndash0000025

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

13 μM

61 μM

(c)

ndash8

ndash10

ndash12

ndash14

ndash16

ndash18

ndash20

ndash2210 20 30 40 50 60

Curr

ent (μA

)

Concentration (μmolL)

R2 = 099489

DA

(d)

000000

ndash000002

ndash000004

ndash000006

ndash000008

ndash000010

Curr

ent (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

01 mM

75 mM

(e)

0

ndash20

ndash40

ndash60

ndash80

ndash1000 1 2 3 4 5 6 7 8

Curr

ent (μA

)

Concentration (mmolL)

R2 = 098595

R2 = 098619

UA

(f )

Figure 5 DPVs of different concentrations of (a) AA in the presence of 20 μMDA and 05mM UA (c) DA in the presence of 15mM AAand 05mM UA and (e) UA in the presence of 075mM AA and 10 μM DA Calibration plots for (b) AA (d) DA and (f) UA

8 International Journal of Analytical Chemistry

36 Study of Anti-Interference Ability Lastly to evaluate theanti-interference ability of PdNPsrGOGCE the interfer-ence of Na+ (d) Clminus (e) Mg2+ (f) SO42minus (g) and glucose (h)with 100-fold concentration in the detection of 1mM AA(a) 50 μM DA (b) and 01mM UA (c) in 01MPB wasconducted by chronoamperometry at a constant potential of+06V for 800 s As shown in Figure 8 with the addition ofAA DA and UA the current signal of PdNPsrGOGCEincreased rapidly with response times of 5 s 5 s and 3 srespectively and the interferents did not produce obvious

effects on the current signal of AA DA and UA As a resultthis proposed sensor was of excellent anti-interferenceability and practical application value

37 Real Samples Detection In order to demonstrate theapplicability of the proposedmethod different concentrations ofAA DA and UA are doped into the human serum samples bythe standard addition method 1e DPV experimental resultsare shown in Table S11e recoveries of the spiked samples were

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

Delt

a I (F

-R) (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

025 mM

35 mM 01 mM

14 mM

3 μM

42 μM

(a)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

00 05 10 15 20 25 30 35 40Concentration (mmolL)

AA

Curr

ent (μA

)

R2 = 099187

(b)

Concentration (μmolL)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

0 10 20 30 40 50

Curr

ent (μA

)

R2 = 099598

R2 = 099248

DA

(c)

Concentration (mmolL)00 02 04 06 08 10 12 14 16

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

Curr

ent (μA

)

R2 = 098765

UA

(d)

Figure 6 DPV curves of different concentrations of AA DA and UA (a) calibration plots for (b) AA (c) DA and (d) UA

Table 1 Analytical parameters for individual selective and simultaneous detection of AA DA and UA at PdNPsrGOGCE

Analytical parameter Analyte Individual detection Selective detection Simultaneous detection

Linear range (μM)AA 300ndash7000 8000ndash20000 750ndash5000 500ndash3500DA 3ndash50 60ndash170 13ndash61 3ndash15 15ndash42UA 50ndash1000 1500ndash4500 500ndash4000 4500ndash7500 300ndash1400

Sensitivity (μA middot μMminus1 middot cmminus2)AA 0069 0028 0107 0079DA 4300 1443 3254 10893 6083UA 0416 0118 0194 0049 0481

International Journal of Analytical Chemistry 9

Table 2 Comparison of different electrodes in the simultaneous detection of AA DA and UA

Electrode pHLinear range (μM)

Sensitivity (μA middot μMminus1 middot cmminus2) RefAA DA UA

MgO nanobeltsGCE 50 25ndash15 25ndash1500198 0028

0125ndash757908

05ndash3 5ndash30283 0962 [30]

SnO2chitosanGCE 70 20ndash2200127

01ndash182773

1ndash1002391 [45]

3DGHa-AuNPsbGCE 70 10ndash7000217

02ndash303897

1ndash601703 [46]

AuNPsbMoS2 nanosheetsGCE 40 12ndash8000481

10ndash3000979

8ndash9000465 [47]

Pd3Pt1cPDDAd-rGOGCE 74 40ndash12000359

4ndash2000639

4ndash4000498 [48]

CBeGCE 70 191ndash3780214

0599ndash1181570

101ndash140680 [49]

PtNP-AuSnfCFPg 70 200ndash120000004

05ndash1000017

25ndash50000003 [50]

PdNPsrGOGCE 72 500ndash35000079

3ndash15 15ndash4210893 6083

300ndash14000481 1is work

a three dimensional graphene hydrogel b gold nanoparticles c Pd-Pt bimetallic nanoparticles d poly(diallyldimethylammonium chloride) e nano-structured carbon black f Pt nanoparticle-modified nanoporous AuSn g Ni-buffered flexible carbon fiber paper

80

70

60

50

40

30

20

10

01 2 3 4 5 6

Electrode number

Curr

ent (μA

)

AADAUA

(a)

0 500 1000 1500 2000Elapsed time (s)

0000007

0000006

0000005

0000004

0000003

0000002

0000001

0000000

Curr

ent (

A)

AA

(b)

0 500 1000 1500 2000Elapsed time (s)

00000035

00000030

00000025

00000020

00000015

00000010

00000005

00000000

Curr

ent (

A)

DA

(c)

0 500 1000 1500 2000Elapsed time (s)

000008

000007

000006

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

UA

(d)

Figure 7 (a) Reproducibility of CQDs-rGOGCE stability of (b) 1mM AA (c) 20 μM DA and (d) 05mM UA

10 International Journal of Analytical Chemistry

detected within the range of 966ndash1085 suggesting theapplicability of the prepared sensor to real samples

4 Conclusions

In summary this paper has proposed a novel approach forthe synthesis of PdNPsrGO nanocomposite by two-step CVelectrodeposition the increased surface area of as-preparedmaterial has contributed to improve the contact probabilitybetween electrode surface and analytes thus elevating thecatalytic activity of the modified electrode which wasconfirmed using CV and EIS After optimizing the experi-mental conditions the sensor showed excellent separationability and fast response for AA DA and UA and has stronganti-interference ability for some common interferingsubstances Besides good reproducibility and stability werealso obtained by this sensor 1e above results revealed thatPdNPsrGOGCE can be a good candidate in the sensingapplication of AA DA and UA in the future

Data Availability

1e generated or analyzed data used to support the findingsof this study are included within the article

Conflicts of Interest

1e authors declare that they have no conflicts of interest

Acknowledgments

1is study was financially supported by the National KeyRampD Program of China (no 2019YFC1709000) NationalNatural Science Foundation of China (NSFC) (nos81973944 and 81503636) National SampT Major Project (no2018ZX09201011) and Youth Talent Promotion Project ofthe China Association for Science and Technology (no 2019-2021ZGZJXH-QNRC001)

Supplementary Materials

Figure S1 EDS characterization of PdNPsrGO nano-composites Figure S2 CV characterization of bare GCE (a)rGOGCE (b) and PdNPsrGOGCE (c) in 20mM potas-sium ferricyanide solution containing 01M KCl Table S1detection of AA DA and UA in real samples (n 3)(Supplementary Materials)

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

Curr

ent (

A)

0 200 400 600 800Time (s)

5 s

180 200 220 240 260 280 300

000005000004000003000002000001000000

Time (s)

AA

d

a

e f g h

(a)

Curr

ent (

A)

Curr

ent (

A)

0000012

0000010

0000008

0000006

0000004

0000002

0000000

ndash00000020 200 400 600 800

Time (s)

5 s180 200 220 240 260 280 300

000002000000180000016000001400000120000010

000008000006000004000002000000

ndash000002

Time (s)

DA

d

b

e f g h

(b)

Curr

ent (

A)Cu

rren

t (A

)

0 200 400 600 800Time (s)

00000010

00000008

00000006

00000004

00000002

00000000

ndash00000002

3 s

200 220 240 260 280Time (s)

000000100000000800000006000000040000000200000000

ndash00000002

UA

d e f g h

c

(c)

Figure 8 Amperometric responses of 1mM AA (a) 50 μM DA (b) and 01mM UA (c) in the presence of 100-fold concentration ofinterferents

International Journal of Analytical Chemistry 11

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 9: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

36 Study of Anti-Interference Ability Lastly to evaluate theanti-interference ability of PdNPsrGOGCE the interfer-ence of Na+ (d) Clminus (e) Mg2+ (f) SO42minus (g) and glucose (h)with 100-fold concentration in the detection of 1mM AA(a) 50 μM DA (b) and 01mM UA (c) in 01MPB wasconducted by chronoamperometry at a constant potential of+06V for 800 s As shown in Figure 8 with the addition ofAA DA and UA the current signal of PdNPsrGOGCEincreased rapidly with response times of 5 s 5 s and 3 srespectively and the interferents did not produce obvious

effects on the current signal of AA DA and UA As a resultthis proposed sensor was of excellent anti-interferenceability and practical application value

37 Real Samples Detection In order to demonstrate theapplicability of the proposedmethod different concentrations ofAA DA and UA are doped into the human serum samples bythe standard addition method 1e DPV experimental resultsare shown in Table S11e recoveries of the spiked samples were

000000

ndash000001

ndash000002

ndash000003

ndash000004

ndash000005

ndash000006

ndash000007

Delt

a I (F

-R) (

A)

0602 04ndash04 ndash02 00Potential (V)

AA DA UA

025 mM

35 mM 01 mM

14 mM

3 μM

42 μM

(a)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

00 05 10 15 20 25 30 35 40Concentration (mmolL)

AA

Curr

ent (μA

)

R2 = 099187

(b)

Concentration (μmolL)

ndash5

ndash10

ndash15

ndash20

ndash25

ndash30

0 10 20 30 40 50

Curr

ent (μA

)

R2 = 099598

R2 = 099248

DA

(c)

Concentration (mmolL)00 02 04 06 08 10 12 14 16

0

ndash10

ndash20

ndash30

ndash40

ndash50

ndash60

ndash70

Curr

ent (μA

)

R2 = 098765

UA

(d)

Figure 6 DPV curves of different concentrations of AA DA and UA (a) calibration plots for (b) AA (c) DA and (d) UA

Table 1 Analytical parameters for individual selective and simultaneous detection of AA DA and UA at PdNPsrGOGCE

Analytical parameter Analyte Individual detection Selective detection Simultaneous detection

Linear range (μM)AA 300ndash7000 8000ndash20000 750ndash5000 500ndash3500DA 3ndash50 60ndash170 13ndash61 3ndash15 15ndash42UA 50ndash1000 1500ndash4500 500ndash4000 4500ndash7500 300ndash1400

Sensitivity (μA middot μMminus1 middot cmminus2)AA 0069 0028 0107 0079DA 4300 1443 3254 10893 6083UA 0416 0118 0194 0049 0481

International Journal of Analytical Chemistry 9

Table 2 Comparison of different electrodes in the simultaneous detection of AA DA and UA

Electrode pHLinear range (μM)

Sensitivity (μA middot μMminus1 middot cmminus2) RefAA DA UA

MgO nanobeltsGCE 50 25ndash15 25ndash1500198 0028

0125ndash757908

05ndash3 5ndash30283 0962 [30]

SnO2chitosanGCE 70 20ndash2200127

01ndash182773

1ndash1002391 [45]

3DGHa-AuNPsbGCE 70 10ndash7000217

02ndash303897

1ndash601703 [46]

AuNPsbMoS2 nanosheetsGCE 40 12ndash8000481

10ndash3000979

8ndash9000465 [47]

Pd3Pt1cPDDAd-rGOGCE 74 40ndash12000359

4ndash2000639

4ndash4000498 [48]

CBeGCE 70 191ndash3780214

0599ndash1181570

101ndash140680 [49]

PtNP-AuSnfCFPg 70 200ndash120000004

05ndash1000017

25ndash50000003 [50]

PdNPsrGOGCE 72 500ndash35000079

3ndash15 15ndash4210893 6083

300ndash14000481 1is work

a three dimensional graphene hydrogel b gold nanoparticles c Pd-Pt bimetallic nanoparticles d poly(diallyldimethylammonium chloride) e nano-structured carbon black f Pt nanoparticle-modified nanoporous AuSn g Ni-buffered flexible carbon fiber paper

80

70

60

50

40

30

20

10

01 2 3 4 5 6

Electrode number

Curr

ent (μA

)

AADAUA

(a)

0 500 1000 1500 2000Elapsed time (s)

0000007

0000006

0000005

0000004

0000003

0000002

0000001

0000000

Curr

ent (

A)

AA

(b)

0 500 1000 1500 2000Elapsed time (s)

00000035

00000030

00000025

00000020

00000015

00000010

00000005

00000000

Curr

ent (

A)

DA

(c)

0 500 1000 1500 2000Elapsed time (s)

000008

000007

000006

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

UA

(d)

Figure 7 (a) Reproducibility of CQDs-rGOGCE stability of (b) 1mM AA (c) 20 μM DA and (d) 05mM UA

10 International Journal of Analytical Chemistry

detected within the range of 966ndash1085 suggesting theapplicability of the prepared sensor to real samples

4 Conclusions

In summary this paper has proposed a novel approach forthe synthesis of PdNPsrGO nanocomposite by two-step CVelectrodeposition the increased surface area of as-preparedmaterial has contributed to improve the contact probabilitybetween electrode surface and analytes thus elevating thecatalytic activity of the modified electrode which wasconfirmed using CV and EIS After optimizing the experi-mental conditions the sensor showed excellent separationability and fast response for AA DA and UA and has stronganti-interference ability for some common interferingsubstances Besides good reproducibility and stability werealso obtained by this sensor 1e above results revealed thatPdNPsrGOGCE can be a good candidate in the sensingapplication of AA DA and UA in the future

Data Availability

1e generated or analyzed data used to support the findingsof this study are included within the article

Conflicts of Interest

1e authors declare that they have no conflicts of interest

Acknowledgments

1is study was financially supported by the National KeyRampD Program of China (no 2019YFC1709000) NationalNatural Science Foundation of China (NSFC) (nos81973944 and 81503636) National SampT Major Project (no2018ZX09201011) and Youth Talent Promotion Project ofthe China Association for Science and Technology (no 2019-2021ZGZJXH-QNRC001)

Supplementary Materials

Figure S1 EDS characterization of PdNPsrGO nano-composites Figure S2 CV characterization of bare GCE (a)rGOGCE (b) and PdNPsrGOGCE (c) in 20mM potas-sium ferricyanide solution containing 01M KCl Table S1detection of AA DA and UA in real samples (n 3)(Supplementary Materials)

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

Curr

ent (

A)

0 200 400 600 800Time (s)

5 s

180 200 220 240 260 280 300

000005000004000003000002000001000000

Time (s)

AA

d

a

e f g h

(a)

Curr

ent (

A)

Curr

ent (

A)

0000012

0000010

0000008

0000006

0000004

0000002

0000000

ndash00000020 200 400 600 800

Time (s)

5 s180 200 220 240 260 280 300

000002000000180000016000001400000120000010

000008000006000004000002000000

ndash000002

Time (s)

DA

d

b

e f g h

(b)

Curr

ent (

A)Cu

rren

t (A

)

0 200 400 600 800Time (s)

00000010

00000008

00000006

00000004

00000002

00000000

ndash00000002

3 s

200 220 240 260 280Time (s)

000000100000000800000006000000040000000200000000

ndash00000002

UA

d e f g h

c

(c)

Figure 8 Amperometric responses of 1mM AA (a) 50 μM DA (b) and 01mM UA (c) in the presence of 100-fold concentration ofinterferents

International Journal of Analytical Chemistry 11

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 10: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

Table 2 Comparison of different electrodes in the simultaneous detection of AA DA and UA

Electrode pHLinear range (μM)

Sensitivity (μA middot μMminus1 middot cmminus2) RefAA DA UA

MgO nanobeltsGCE 50 25ndash15 25ndash1500198 0028

0125ndash757908

05ndash3 5ndash30283 0962 [30]

SnO2chitosanGCE 70 20ndash2200127

01ndash182773

1ndash1002391 [45]

3DGHa-AuNPsbGCE 70 10ndash7000217

02ndash303897

1ndash601703 [46]

AuNPsbMoS2 nanosheetsGCE 40 12ndash8000481

10ndash3000979

8ndash9000465 [47]

Pd3Pt1cPDDAd-rGOGCE 74 40ndash12000359

4ndash2000639

4ndash4000498 [48]

CBeGCE 70 191ndash3780214

0599ndash1181570

101ndash140680 [49]

PtNP-AuSnfCFPg 70 200ndash120000004

05ndash1000017

25ndash50000003 [50]

PdNPsrGOGCE 72 500ndash35000079

3ndash15 15ndash4210893 6083

300ndash14000481 1is work

a three dimensional graphene hydrogel b gold nanoparticles c Pd-Pt bimetallic nanoparticles d poly(diallyldimethylammonium chloride) e nano-structured carbon black f Pt nanoparticle-modified nanoporous AuSn g Ni-buffered flexible carbon fiber paper

80

70

60

50

40

30

20

10

01 2 3 4 5 6

Electrode number

Curr

ent (μA

)

AADAUA

(a)

0 500 1000 1500 2000Elapsed time (s)

0000007

0000006

0000005

0000004

0000003

0000002

0000001

0000000

Curr

ent (

A)

AA

(b)

0 500 1000 1500 2000Elapsed time (s)

00000035

00000030

00000025

00000020

00000015

00000010

00000005

00000000

Curr

ent (

A)

DA

(c)

0 500 1000 1500 2000Elapsed time (s)

000008

000007

000006

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

UA

(d)

Figure 7 (a) Reproducibility of CQDs-rGOGCE stability of (b) 1mM AA (c) 20 μM DA and (d) 05mM UA

10 International Journal of Analytical Chemistry

detected within the range of 966ndash1085 suggesting theapplicability of the prepared sensor to real samples

4 Conclusions

In summary this paper has proposed a novel approach forthe synthesis of PdNPsrGO nanocomposite by two-step CVelectrodeposition the increased surface area of as-preparedmaterial has contributed to improve the contact probabilitybetween electrode surface and analytes thus elevating thecatalytic activity of the modified electrode which wasconfirmed using CV and EIS After optimizing the experi-mental conditions the sensor showed excellent separationability and fast response for AA DA and UA and has stronganti-interference ability for some common interferingsubstances Besides good reproducibility and stability werealso obtained by this sensor 1e above results revealed thatPdNPsrGOGCE can be a good candidate in the sensingapplication of AA DA and UA in the future

Data Availability

1e generated or analyzed data used to support the findingsof this study are included within the article

Conflicts of Interest

1e authors declare that they have no conflicts of interest

Acknowledgments

1is study was financially supported by the National KeyRampD Program of China (no 2019YFC1709000) NationalNatural Science Foundation of China (NSFC) (nos81973944 and 81503636) National SampT Major Project (no2018ZX09201011) and Youth Talent Promotion Project ofthe China Association for Science and Technology (no 2019-2021ZGZJXH-QNRC001)

Supplementary Materials

Figure S1 EDS characterization of PdNPsrGO nano-composites Figure S2 CV characterization of bare GCE (a)rGOGCE (b) and PdNPsrGOGCE (c) in 20mM potas-sium ferricyanide solution containing 01M KCl Table S1detection of AA DA and UA in real samples (n 3)(Supplementary Materials)

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

Curr

ent (

A)

0 200 400 600 800Time (s)

5 s

180 200 220 240 260 280 300

000005000004000003000002000001000000

Time (s)

AA

d

a

e f g h

(a)

Curr

ent (

A)

Curr

ent (

A)

0000012

0000010

0000008

0000006

0000004

0000002

0000000

ndash00000020 200 400 600 800

Time (s)

5 s180 200 220 240 260 280 300

000002000000180000016000001400000120000010

000008000006000004000002000000

ndash000002

Time (s)

DA

d

b

e f g h

(b)

Curr

ent (

A)Cu

rren

t (A

)

0 200 400 600 800Time (s)

00000010

00000008

00000006

00000004

00000002

00000000

ndash00000002

3 s

200 220 240 260 280Time (s)

000000100000000800000006000000040000000200000000

ndash00000002

UA

d e f g h

c

(c)

Figure 8 Amperometric responses of 1mM AA (a) 50 μM DA (b) and 01mM UA (c) in the presence of 100-fold concentration ofinterferents

International Journal of Analytical Chemistry 11

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 11: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

detected within the range of 966ndash1085 suggesting theapplicability of the prepared sensor to real samples

4 Conclusions

In summary this paper has proposed a novel approach forthe synthesis of PdNPsrGO nanocomposite by two-step CVelectrodeposition the increased surface area of as-preparedmaterial has contributed to improve the contact probabilitybetween electrode surface and analytes thus elevating thecatalytic activity of the modified electrode which wasconfirmed using CV and EIS After optimizing the experi-mental conditions the sensor showed excellent separationability and fast response for AA DA and UA and has stronganti-interference ability for some common interferingsubstances Besides good reproducibility and stability werealso obtained by this sensor 1e above results revealed thatPdNPsrGOGCE can be a good candidate in the sensingapplication of AA DA and UA in the future

Data Availability

1e generated or analyzed data used to support the findingsof this study are included within the article

Conflicts of Interest

1e authors declare that they have no conflicts of interest

Acknowledgments

1is study was financially supported by the National KeyRampD Program of China (no 2019YFC1709000) NationalNatural Science Foundation of China (NSFC) (nos81973944 and 81503636) National SampT Major Project (no2018ZX09201011) and Youth Talent Promotion Project ofthe China Association for Science and Technology (no 2019-2021ZGZJXH-QNRC001)

Supplementary Materials

Figure S1 EDS characterization of PdNPsrGO nano-composites Figure S2 CV characterization of bare GCE (a)rGOGCE (b) and PdNPsrGOGCE (c) in 20mM potas-sium ferricyanide solution containing 01M KCl Table S1detection of AA DA and UA in real samples (n 3)(Supplementary Materials)

000005

000004

000003

000002

000001

000000

Curr

ent (

A)

Curr

ent (

A)

0 200 400 600 800Time (s)

5 s

180 200 220 240 260 280 300

000005000004000003000002000001000000

Time (s)

AA

d

a

e f g h

(a)

Curr

ent (

A)

Curr

ent (

A)

0000012

0000010

0000008

0000006

0000004

0000002

0000000

ndash00000020 200 400 600 800

Time (s)

5 s180 200 220 240 260 280 300

000002000000180000016000001400000120000010

000008000006000004000002000000

ndash000002

Time (s)

DA

d

b

e f g h

(b)

Curr

ent (

A)Cu

rren

t (A

)

0 200 400 600 800Time (s)

00000010

00000008

00000006

00000004

00000002

00000000

ndash00000002

3 s

200 220 240 260 280Time (s)

000000100000000800000006000000040000000200000000

ndash00000002

UA

d e f g h

c

(c)

Figure 8 Amperometric responses of 1mM AA (a) 50 μM DA (b) and 01mM UA (c) in the presence of 100-fold concentration ofinterferents

International Journal of Analytical Chemistry 11

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 12: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

References

[1] D Wen S Guo S Dong and E Wang ldquoUltrathin Pdnanowire as a highly active electrodematerial for sensitive andselective detection of ascorbic acidrdquo Biosensors and Bio-electronics vol 26 no 3 pp 1056ndash1061 2010

[2] L Yang N Huang Q Lu et al ldquoA quadruplet electrochemicalplatform for ultrasensitive and simultaneous detection ofascorbic acid dopamine uric acid and acetaminophen basedon a ferrocene derivative functional Au NPscarbon dotsnanocomposite and graphenerdquo Analytica Chimica Actavol 903 pp 69ndash80 2016

[3] X Zhang L-X Ma and Y-C Zhang ldquoElectrodeposition ofplatinum nanosheets on C 60 decorated glassy carbon elec-trode as a stable electrochemical biosensor for simultaneousdetection of ascorbic acid dopamine and uric acidrdquo Elec-trochimica Acta vol 177 pp 118ndash127 2015

[4] K Ghanbari and N Hajheidari ldquoZnO-CuxOpolypyrrolenanocomposite modified electrode for simultaneous deter-mination of ascorbic acid dopamine and uric acidrdquo Ana-lytical Biochemistry vol 473 pp 53ndash62 2015

[5] F Yang J Wang Y Cao L Zhang and X Zhang ldquoA highlysensitive ascorbic acid sensor based on carbon-supportedCoPd nanoparticlesrdquo Sensors and Actuators B Chemicalvol 205 pp 20ndash25 2014

[6] X Zhang Y Cao S Yu F Yang and P Xi ldquoAn electrochemicalbiosensor for ascorbic acid based on carbon-supported PdNinanoparticlesrdquo Biosensors and Bioelectronics vol 44 pp 183ndash1902013

[7] H-M Wang C-C Wang A-J Wang et al ldquoGreen synthesisof Pd nanocones as a novel and effective electro-chemiluminescence illuminant for highly sensitive detectionof dopaminerdquo Sensors and Actuators B Chemical vol 281pp 588ndash594 2019

[8] H Bagheri N Pajooheshpour B Jamali S Amidi A Hajianand H Khoshsafar ldquoA novel electrochemical platform forsensitive and simultaneous determination of dopamine uric acidand ascorbic acid based on Fe3O4SnO2Gr ternary nano-compositerdquo Microchemical Journal vol 131 pp 120ndash129 2017

[9] M Wang Y Gao J Zhang and J Zhao ldquoHighly dispersedcarbon nanotube in new ionic liquid-graphene oxidesaqueous dispersions for ultrasensitive dopamine detectionrdquoElectrochimica Acta vol 155 pp 236ndash243 2015

[10] G Li Y Xia Y Tian et al ldquoReview-recent developments ongraphene-based electrochemical sensors toward nitriterdquoJournal of the Electrochemical Society vol 166 no 12pp B881ndashB895 2019

[11] Q Li Y Xia X Wan et al ldquoMorphology-dependent MnO2nitrogen-doped graphene nanocomposites for simultaneousdetection of trace dopamine and uric acidrdquo Materials Scienceand Engineering C vol 109 p 110615 2020

[12] X Wan S Yang Z Cai et al ldquoFacile synthesis of MnO2nanoflowersN-doped reduced graphene oxide composite andits application for simultaneous determination of dopamineand uric acidrdquo Nanomaterials vol 9 no 6 p 847 2019

[13] S Daemi A A Ashkarran A Bahari and S GhasemildquoFabrication of a gold nanocagegraphene nanoscale platformfor electrocatalytic detection of hydrazinerdquo Sensors and Ac-tuators B Chemical vol 245 pp 55ndash65 2017

[14] N Tukimin J Abdullah and Y Sulaiman ldquoElectrodepositionof poly(34-ethylenedioxythiophene)reduced graphene ox-idemanganese dioxide for simultaneous detection of uricacid dopamine and ascorbic acidrdquo Journal of Electroanalyt-ical Chemistry vol 820 pp 74ndash81 2018

[15] Q He J Liu X Liu et al ldquoA promising sensing platformtoward dopamine using MnO2 nanowireselectro-reducedgraphene oxide compositesrdquo Electrochimica Acta vol 296pp 683ndash692 2019

[16] C Mu H Lu J Bao and Q Zhang ldquoVisual colorimetriclsquoturn-offrsquo biosensor for ascorbic acid detection based onhypochlorite-33prime55prime-Tetramethylbenzidine systemrdquo Spec-trochimica Acta Part A Molecular and Biomolecular Spec-troscopy vol 201 pp 61ndash66 2018

[17] E Fazio S Spadaro M Bonsignore et al ldquoMolybdenumoxide nanoparticles for the sensitive and selective detection ofdopaminerdquo Journal of Electroanalytical Chemistry vol 814pp 91ndash96 2018

[18] T Rohani andM A Taher ldquoNovel functionalizedmultiwalledcarbon nanotube-glassy carbon electrode for simultaneousdetermination of ascorbic acid and uric acidrdquoArabian Journalof Chemistry vol 11 no 2 pp 214ndash220 2018

[19] Q Zhang Z Mao K Wang N T S Phan and F ZhangldquoMicrowave-assisted aqueous carbon-carbon cross-couplingreactions of aryl chlorides catalysed by reduced grapheneoxide supported palladium nanoparticlesrdquo Green Chemistryvol 22 no 10 pp 3239ndash3247 2020

[20] B Murugesan N Pandiyan M Arumugam et al ldquoFabrica-tion of palladium nanoparticles anchored polypyrrole func-tionalized reduced graphene oxide nanocomposite forantibiofilm associated orthopedic tissue engineeringrdquo AppliedSurface Science vol 510 p 145403 2020

[21] A Wong A M Santos R Da Fonseca Alves F C VicentiniO Fatibello-Filho and M Del Pilar Taboada SotomayorldquoSimultaneous determination of direct yellow 50 tryptophancarbendazim and caffeine in environmental and biologicalfluid samples using graphite pencil electrode modified withpalladium nanoparticlesrdquo Talanta vol 222 p 121539 2021

[22] H Li S Wang F Cui et al ldquoSensitive and selective detectionof puerarin based on the hybrid of reduced graphene oxideand molecularly imprinted polymerrdquo Journal of Pharma-ceutical and Biomedical Analysis vol 185 Article ID 1132212020

[23] N Gao C He M Ma et al ldquoElectrochemical co-depositionsynthesis of Au-ZrO2-graphene nanocomposite for a non-enzymatic methyl parathion sensorrdquo Analytica Chimica Actavol 1072 pp 25ndash34 2019

[24] T Wu T Li Z Liu Y Guo and C Dong ldquoElectrochemicalsensor for sensitive detection of triclosan based on graphenepalladium nanoparticles hybridsrdquo Talanta vol 164pp 556ndash562 2017

[25] W Yi Z Li C Dong H-W Li and J Li ldquoElectrochemicaldetection of chloramphenicol using palladium nanoparticlesdecorated reduced graphene oxiderdquo Microchemical Journalvol 148 pp 774ndash783 2019

[26] D R Kulkarni S J Malode K Keerthi Prabhu N H AyachitR M Kulkarni and N P Shetti ldquoDevelopment of a novelnanosensor using Ca-doped ZnO for antihistamine drugrdquoMaterials Chemistry and Physics vol 246 Article ID 1227912020

[27] X Zhang S Yu W He et al ldquoElectrochemical sensor basedon carbon-supported NiCoO2 nanoparticles for selectivedetection of ascorbic acidrdquo Biosensors and Bioelectronicsvol 55 pp 446ndash451 2014

[28] Y Wang Y Huang B Wang T Fang J Chen and C Liangldquo1ree-dimensional porous graphene for simultaneous de-tection of dopamine and uric acid in the presence of ascorbicacidrdquo Journal of Electroanalytical Chemistry vol 782pp 76ndash83 2016

12 International Journal of Analytical Chemistry

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13

Page 13: SimultaneousDetectionofAscorbicAcid,Dopamine,andUric ...W k W k LW Lk ,W UoncentratioxJ©jN UurrenxJ c IN R LxOxWyfi/f, R LxOxWyfi/-k, II (b) Wy Wy Wy Wy Wy Wy WyWWWW,W WyWWWW,k

[29] X-B Li M M Rahman G-R Xu and J-J Lee ldquoHighly sensitiveand selective detection of dopamine at poly(chromotrope2B)-Modified glassy carbon electrode in the presence of uric acidand ascorbic acidrdquo Electrochimica Acta vol 173 pp 440ndash4472015

[30] M Li W Guo H Li W Dai and B Yang ldquoElectrochemicalbiosensor based on one-dimensional MgO nanostructures forthe simultaneous determination of ascorbic acid dopamineand uric acidrdquo Sensors and Actuators B Chemical vol 204pp 629ndash636 2014

[31] S Shrestha R J Mascarenhas O J DrsquoSouza et al ldquoAm-perometric sensor based on multi-walled carbon nanotubeand poly (Bromocresol purple) modified carbon paste elec-trode for the sensitive determination of L-tyrosine in food andbiological samplesrdquo Journal of Electroanalytical Chemistryvol 778 pp 32ndash40 2016

[32] X Chen G Zhang L Shi S Pan W Liu and H Pan ldquoAuZnO hybrid nanocatalysts impregnated in N-doped graphenefor simultaneous determination of ascorbic acid acetamin-ophen and dopaminerdquo Materials Science and Engineering Cvol 65 pp 80ndash89 2016

[33] R Sha and S Badhulika ldquoFacile green synthesis of reducedgraphene oxidetin oxide composite for highly selective andultra-sensitive detection of ascorbic acidrdquo Journal of Elec-troanalytical Chemistry vol 816 pp 30ndash37 2018

[34] X Wang Z You H Sha Y Cheng H Zhu and W SunldquoSensitive electrochemical detection of dopamine with aDNAgraphene bi-layer modified carbon ionic liquid elec-troderdquo Talanta vol 128 pp 373ndash378 2014

[35] E Ergun S Kart D K Zeybek and B Zeybek ldquoSimultaneouselectrochemical determination of ascorbic acid and uric acidusing poly(glyoxal-bis(2-hydroxyanil)) modified glassy car-bon electroderdquo Sensors and Actuators B Chemical vol 224pp 55ndash64 2016

[36] C Wang Z Xiong P Sun R Wang X Zhao and Q WangldquoFacile longitudinal unzipped multiwalled carbon nanotubesincorporated overoxidized poly(p-aminophenol) modifiedelectrode for sensitive simultaneous determination of dopa-mine uric acid and tryptophanrdquo Journal of ElectroanalyticalChemistry vol 801 pp 395ndash402 2017

[37] L Zhang J Feng K-C Chou L Su and X Hou ldquoSi-multaneously electrochemical detection of uric acid andascorbic acid using glassy carbon electrode modified withchrysanthemum-like titanium nitriderdquo Journal of Elec-troanalytical Chemistry vol 803 pp 11ndash18 2017

[38] X Zhang Y-C Zhang and L-X Ma ldquoOne-pot facile fab-rication of graphene-zinc oxide composite and its enhancedsensitivity for simultaneous electrochemical detection ofascorbic acid dopamine and uric acidrdquo Sensors and ActuatorsB Chemical vol 227 pp 488ndash496 2016

[39] K Ghanbari and M Moloudi ldquoFlower-like ZnO decoratedpolyanilinereduced graphene oxide nanocomposites for si-multaneous determination of dopamine and uric acidrdquo An-alytical Biochemistry vol 512 pp 91ndash102 2016

[40] A Savk B Ozdil B Demirkan et al ldquoMultiwalled carbonnanotube-based nanosensor for ultrasensitive detection ofuric acid dopamine and ascorbic acidrdquoMaterials Science andEngineering C vol 99 pp 248ndash254 2019

[41] P S Ganesh and B E K Swamy ldquoSimultaneous electro-analysis of norepinephrine ascorbic acid and uric acid usingpoly(glutamic acid) modified carbon paste electroderdquo Journalof Electroanalytical Chemistry vol 752 pp 17ndash24 2015

[42] M M Rahman N S Lopa K Kim and J-J Lee ldquoSelectivedetection of l-tyrosine in the presence of ascorbic acid

dopamine and uric acid at poly(thionine)-modified glassycarbon electroderdquo Journal of Electroanalytical Chemistryvol 754 pp 87ndash93 2015

[43] C Dincer R Ktaich E Laubender et al ldquoNanocrystallineboron-doped diamond nanoelectrode arrays for ultrasensitivedopamine detectionrdquo Electrochimica Acta vol 185 pp 101ndash106 2015

[44] Q Yao H Y Long L Ma et al ldquoEnhanced selectivity ofboron doped diamond electrodes for the detection of dopa-mine and ascorbic acid by increasing the film thicknessrdquoApplied Surface Science vol 390 pp 882ndash889 2016

[45] S Selvarajan A Suganthi and M Rajarajan ldquoA facile ap-proach to synthesis of mesoporous SnO2chitosan nano-composite modified electrode for simultaneous determinationof ascorbic acid dopamine and uric acidrdquo Surfaces and In-terfaces vol 7 pp 146ndash156 2017

[46] Q Zhu J Bao D Huo et al ldquo3D Graphene hydrogel-goldnanoparticles nanocomposite modified glassy carbon elec-trode for the simultaneous determination of ascorbic aciddopamine and uric acidrdquo Sensors and Actuators B Chemicalvol 238 pp 1316ndash1323 2017

[47] H L Zou B L Li H Q Luo and N B Li ldquo0D-2D heter-ostructures of Au nanoparticles and layered MoS2 for si-multaneous detections of dopamine ascorbic acid uric acidand nitriterdquo Sensors and Actuators B Chemical vol 253pp 352ndash360 2017

[48] J Yan S Liu Z Zhang et al ldquoSimultaneous electrochemicaldetection of ascorbic acid dopamine and uric acid based ongraphene anchored with Pd-Pt nanoparticlesrdquo Colloids andSurfaces B Biointerfaces vol 111 pp 392ndash397 2013

[49] F C Vicentini P A Raymundo-Pereira B C JanegitzS A S Machado and O Fatibello-Filho ldquoNanostructuredcarbon black for simultaneous sensing in biological fluidsrdquoSensors and Actuators B Chemical vol 227 pp 610ndash6182016

[50] H Yang J Zhao M Qiu et al ldquoHierarchical bi-continuous Ptdecorated nanoporous Au-Sn alloy on carbon fiber paper forascorbic acid dopamine and uric acid simultaneous sensingrdquoBiosensors and Bioelectronics vol 124-125 pp 191ndash198 2019

International Journal of Analytical Chemistry 13