Anantapur, AP ppt

WEL COME

Analytical Chemistry Laboratory, Department of

Chemistry, Shivaji University, Kolhapur, 416 004

India

Prof. M. A. Anuse

E-mail: [email protected]

Synergistic Solvent Extraction and Spectrophotometric Determination of Coinage Metals using Pyrimidine – 2 – thiol in presence of

pyridine

CHEMICAL ANALYSIS It involves two steps 1) Separation of desired constituents 2) Measurement of the amount or concentration of this constituent

METHODS OF ESTIMINATION 1) Spectrophotometry 2) Spectrography 3) Polarographic Method These methods minimize the need of separation step preceding the measurement step. However, with rapid growth of chemical technology, the analytical chemistry is called upon to deal with the mixtures of increasing complexity. Many metals have assumed industrial significance. The use of titanium, tantalum, niobium and zirconium as a pure metal or as important high temperature alloy constituents. Germanium is the rapidly expanding transistor field. Uranium, thorium, lanthanides and actinides in nuclear energy programme has forced the analytical chemist to take cognizance. Hence there is need for the separation steps and then constituent is subjected to analysis.

Solvent Extraction

Versatile and popular method of separation

Does not need any sophisticated apparatus or instrumentation excepting a separatory funnel

Applicable to both tracer and macro amounts of metal ions

Useful for purpose of preparation, purification Enrichment, Separation and analysis (micro, macro)

Elegant, simple, rapid and wide scope

Highlights of Solvent Extraction

i) Phase rule:As per the phase rule of Gibb's et. al.

P + V = C + 2 Where P = Phase, C= components , V = degree of freedom.

In solvent extraction,

P = 2 phase namely aqueous and organic phase, C = 1 is the component viz. solute,

V = 1 in solvent and water phase and at constant temp. and pressures

Thus, 2+ 1 = 1+ 2 P + V = C + 2

Basic principles of solvent extraction

ii) Distribution Coefficient (KD) and distribution ratio (D):

According to Nernst distribution law if [X1] is concentration of solute in phase 1 and if [X2] is the concentration of solute in phase 2 at equilibrium X1, X2

i.e [X2] KD = --------------- KD = Partition coefficient [X1] This partition or distribution coefficient is independent of the total solute concentration in either of the phases. In the above expression for KD. We have not considered the activity coefficient of the species in the organic as well as in the aqueous phase. We therefore use the term distribution ratio (D) to account for the total concentration of the species in two phases. In the circumstances we have distribution ratio (D) as,

Total concentration of species in the organic phaseD = ------------------------------------------------------------------------- Total concentration of species in the aqueous phase

(iii) Relation between percentage extraction (% E) and distribution ratio (D)Now assuming if there is no association, dissociation or polymerization in the phases then under the idealised condition, KD would be equal to D. In practical work, instead of using term KD or D, the term percentage extraction (% E) is preferred to use which is related to distribution ratio (D) by an expression

D =(V aq/V org) E

100 - Ewhen volumes of organic and aqueous phases are equal, D reduces to

D = E100 - E

when E = 100, extraction is considered to be quantitative, under these circumstances,

D = 100100 - 100 = Infinity

100 D • % E = --------------- D + (Vw / Vo)

D1 Kf1 KDx1

• α = ----- = -------------

D2 Kf2 KDx2

• α = Separation factor

% Extraction

DD

0.0 50 100

Fig: Relation of distribution ratio to percentage extraction

Classification of extraction systems

The extraction systems can be classified on the basis of nature of extraction species

1.Chelate extraction : Formation of chelate or close ring structure is called

as chelate extraction. e.g. the extraction of uranium with 8-

hydroxyquinoline(oxine)

N

OUO 2/2

2) Extraction by solvation :

The extracted species gets solvated into the organic phase. e.g. Extraction of Iron (III) from 6M HCl with diethyl ether

• Fe 3+ + 4 Cl- FeCl4-

• Fecl4- + H+ [H+, FeCl4

- ] • {(C2H5)2O : H+, FeCl4 [(C2H5)2O]2

-

• Oxygen atom of the solvent molecule coordinate with metal ion – oxonium extraction system.

3) Ion - pair formation : The extraction proceed with the formation

of neutral unchanged species fets extracted into organic phase.Mn+ + b B ↔ MBb

n+

MBbn+ + nX- ↔ (MBb

n+, nX- ) cationic complexWhere B = Neutral ligand X = anion M = metalMn+ + (n-a)X- ↔ Mxa-

n+a+ aY+ ↔ (aY+, MXa-n+a) o

anionic complexe.g. 1) Extraction of Cu(II) with 1, 10 phenanthroline in CHCl3. [Cu (Phen)2

+; 2ClO4-] Cationic complex.

2) Iron (III) with ether is anionic type. [H(ether)+, FeCl4 (ether)-]

4) Synergic Extraction: There is enhancement in extraction of

Uranium with TBP or HTTA

Although either TBP or HTTA are individually capable of extraction of Uranium(VI) if one uses mixture of these two extractants one encounters enhanced the extraction

UO2(H2O)x2+

(aq) + 2 HTTA UO2(TTA)2 (H2O)x (org) + 2H+

(aq)

UO2(TTA)2 (H2O)x (org) + TBP(org) UO2 (TTA)2 TBP(org) + H2O

Typical Structure for : UO2(TTA)2TBP (CN = 6)

Types ofTypes ofDerivatives of Pyrimidine-2-Derivatives of Pyrimidine-2-

thiolthiol

I) 1-( 2’-nitro-4’-tolyl)-4,4,6-trimethyl-(1H,4H)-2-pyrimidine thiol

[2’-nitro-4’-tolyl TPT]

N

NCH 3 C H 3

CH 3 SHN

CH3

O 2NH

Talanta, 30(5) 1983, 323 -327.

II) 1-(2’,4’,6’- triclorophenyl)- 4,4,6 – trimethyl- ( 1H, 4H) – 2- pyrimidinethiol

N

NCH 3 C H 3

CH 3 SH

Cl

Cl Cl

Talanta, 32(10) 1985, 1008 – 1010.

III) 1-(2’,4’-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol

N

NCH 3 C H 3

CH 3 SHN

NO 2

O 2NH

Talanta 82 2010 1088-1095

Synergistic extraction of metal ions has various advantages over ordinary liquid-liquid solvent extraction system

Enhancement of extractability.

Widening the optimum concentration pH range.

Stabilization of extracted species by forming an adduct .

Synthesis ofSynthesis of

1-(2’,4’-dinitro aminophenyl)-4,4,6,-1-(2’,4’-dinitro aminophenyl)-4,4,6,-

trimethyl 1,4-dihydropyrimidine-2-thioltrimethyl 1,4-dihydropyrimidine-2-thiol

N

NCH 3 C H 3

CH 3 SHN

NO 2

O 2NH

CH3

CH3

CH3

ONH4SCN

H2SO4

CH3 C

NCS

CH3

CH2 CH3

4-m ethyl-pent-3-ene-2-one

+

15 m in

C

O

2-m ethyl-2-isothiocynato-4-pentanone

Step I: Synthesis of 2-methyl-2-isothiocyanato-4-pentanone

O

SCN

H3C CH3

H3C

CH2

NH-NH2

NO 2

O 2N

H 2SO 4

O 2N

NO 2

HN

N

NSH

+

2-m ethyl-2-isothiocyanato-4-pentanone 2,4 -dinitrophenyl hydrazine

Conc.Reflux, 30 m in

C C

EtO H

1-(2’,4’-dinitro am inophenyl)-4,4,6-trim ethyl-1,4-dihydropyrimidine-2-thiol

Scheme IIStep II: Synthesis of 2-methyl-2-

isothiocyanato-4-pentanone

0

1

2

3

4

5

6

7

200 300 400 500 600 700

W avelength, nm

Abso

rban

ceA

B

Absorbance spectrum of 2’,4’-dinitro APTPT in chloroform A = 0.0002 mol L-1 2’,4’-dinitro APTPT Vs chloroform B = 0.0001 mol L-1 2’,4’-dinitro APTPT Vs chloroform

UV spectrum of 2’,4’-dinitro APTPT

IR (KBr): 3351 (N - H), 3202 (S - H), 2962 (Aromatic C = C), 1617 (C = C), 1517 (C = N)

IR spectrum of 2’,4’-dinitro APTPT

24

SYNERGISTIC LIQUID-LIQUID EXTRACTION AND SPECTROPHOTOMETRIC DETERMINATION OF COPPER(II) WITH 1-(2’,4’-DINITRO AMINOPHENYL)-4,4,6-TRIMETHYL-1,4-DIHYDROPYRIMIDINE-2-THIOL: ANALYSIS OF REAL SAMPLES

Impact Factor:1.770

25

EXPERIMENTAL SECTIONApparatus: Absorption measurements were carried out with an Elico digital spectrophotometer model CL-27 using 1 cm quartz cell. The pH values were determined with an Elico digital pH meter model LI-120.

Glass vessels were cleaned by soaking in acidified solutions of K2Cr2O7, followed by washing with soap water and rinsed two times with water. Reagents: Standard stock solution of copper(II) was prepared by dissolving 3.934 g of copper sulphate pentahydrate (CuSO4.5H2O Merck), in of water. The solution was made up to one liter (1mg/mL) and standardized by titrimetrically. The working solutions were prepared by dilution the stock solution suitably with water. All other chemicals and solvents used were of analytical reagents grade. Double distilled water was used throughout the experiment.

26

GENERAL EXTRACTION AND DETERMINATION PROCEDURE FOR Cu(II)An aliquot of the sample solution

containing 30 μg/cm3 copper(II) solution was taken and pH was adjusted to 9.5 with dil. hydrochloric acid and sodium hydroxide in 25 cm3 volume. The solution was transferred into a 125 cm3 separatory funnel and thoroughly mixed with 5.0 cm3 of a 0.01 M 2’,4’-dinitro APTPT and 5.0 cm3 of 0.5 M pyridine in chloroform for 15 min. The two phages were allowed to separate and the organic layer having a green colour was transferred to a 10 cm3 standard flask and made up to the mark with chloroform. The absorbance of the organic phase was measured at 445 and 645 nm against reagent blank. Unknown amount of copper(II) was determined from the calibration graph prepared in the same manner.

27

An aliquot of the sample solution containing 30 μg/cm3 Cu(II)

pH was adjusted to 9.5

Solution was transferred into a 125 cm3 separatory funnel

Mixed with 5.0 cm3 of a 0.01 M 2’,4’-dinitro APTPT and 5.0 cm3 of 0.5 M pyridine in chloroformTwo phases were allowed to separate

Absorbance of the green organic phase was

measured at 445 nm and 645 nm against reagent blank

Equilibrium time = 15 min

28

1. Absorption Spectra

RESULTS AND DISCUSSION

(A) Absorption spectra of 2’,4’-dinitro APTPT vs. Chloroform blank:(B) Absorption spectra of Cu(II)-2’,4’-dinitroAPTPT-pyridine complex vs. 2’,4’- dinitro APTPT blank: i) Cu(II) = 30 μg/cm3, ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.01 M, iii) pH = 9.5, v) Pyridine = 5 cm3 of 0.5 M, v) Shaking time= 15 min, vi) Scan = 300 to 800 nm, vii) Blank = Reagent

00.10.20.30.40.50.60.70.80.91

200 300 400 500 600 700 800W avelength, nm

Absorptio

n

Reagent, 415 nm

C olouredcom plex, 445 nmand 645 nm

29

00.050.10.150.20.250.30.350.40.45

0 2 4 6 8 10 12 14pH

Absorbance

Ab. at 445 nmwith Py Ab. at 645 nmwith PyAb. at 445 nmwithout PyAb. at 645 nmwithout Py

00.050.10.150.20.250.30.350.40.45

0 0.002 0.004 0.006 0.008 0.01 0.012

Reagent concentration

Absorbance

Ab. at 445 nmwith Py Ab. at 645 nmwith PyAb at 445 nmwithout PyAb. at 645 nmwithout Py

2. Effect of pHi) Cu(II) = 30 μg/cm3

ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.01 M

iii) pH = 8.5 to 10.2 (9.5)With pyridine absorbance =

0.382Without pyridine absorbance =

0.180iv) Pyridine = 5 cm3 of 0.5 M

v) Shaking time = 15 min vi) λmax = 445 nm and 645 nm, vii) Blank = Reagent

3. Effect of 2’, 4’-dinitro APTPT Concentration i) Cu(II) = 30 μg/cm3

ii) 2’,4’-dinitro APTPT = 0.0005 to 0.01 M ( 5 cm3 of 0.01M) iii) pyridine = 5 cm3 of 0.5 Miv) pH = 9.5v) shaking time = 15 min, vi) λmax = 445 nm and 645 nm, vii) Blank = Reagent

30

4. Effect of Shaking Time

00.050.10.150.20.250.30.350.40.45

0 5 10 15 20 25 30 35Tim e in M in

Absorbance

At 445 nm with py

At 645 nm with py

At 445 nm withoutpyAt 645 nm withoutpy

i) Cu(II) = 30 μg/cm3 ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.01Miii) Pyridine = 5 cm3 of 0.5 Miv) pH = 9.5 v) Shaking time = 0 sec to 20 min (15 min)vi) λmax = 445 nm and 645 nm, vii) Blank = Reagent

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0 1 2 3 4 5 6

Pyridine conc.cm 3 ( 0.5 M )

Absorbance

Ab at 445 nmAb. at 645 nm

5. Effect of Concentration of Synergent i) Cu(II) = 30 μg/cm3

ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.01 Miii) Pyridine = 0 to 5 cm3 of 0.5 M ( 5 cm3)iv) pH = 9.5 v) Shaking time = 15 min vi) λmax = 445 nm 645 nm, vii) Blank = Reagent

31

6. Effect of Colour

Stability

00.050.10.150.20.250.30.350.40.45

0 10 20 30 40Tim e in h

Absorbance

Ab at 445 nmwith PyAb at 645 nmwith PyAb at 445 nmwithout PyAb at 645 nmwithout Py

i) Cu(II) = 30 μg/cm3

ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.01iii) M pyridine = 5 cm3 of 0.5 Miv) pH = 9.5v) Shaking time = 15 min vi) λmax = 445 nm and 645 nm, vii) Blank = Reagent viii) Colour stability = > 48

h

0

0.2

0.4

0.6

0.8

1

0 20 40 60 80 100Cu(II) ppm

Absorbance

At 445 nm with pyAt 645 nm with py7. Validity of Beer’s

Law

i) Cu(II) = 10 to 80 μg/cm3 ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.01 M iii) pyridine = 5 cm3 of 0.5 M iv) pH = 9.5 v) Shaking time = 15 min vi) λmax = 445 nm and 645 nmvii) Blank = Reagent

32

i) Cu(II) = 20 to 60 μg/cm3 ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.01 M iii) Pyridine = 5 cm3 of 0.5 M iv) pH = 9.5 v) Shaking time = 15 min vi) λmax = 445 nm and 645 nmvii) Blank = Reagent

020406080100

0 1 2 3 4Log ppm , Cu(II)

%T

At 445 nmAt 645 nm

8. Ringbom’s plot for determination of optimum concentration of

Cu(II)

33

8. Determination of the Stoichiometry of the Complex.

-2-1.5-1

-0.50

0.51

1.52

2.5

-5 -4 -3 -2 -1Log C [2, 4-dinitro APTPT]

Absorbance

Ab at 645 nm w ithoutPyAb at 445 nm w ithoutPyAb at 645 nm w ith Py

Ab at 445 nm w ith Py

1.82 1.86

2.03

2.07

1) Slope ratio method (Fixed pyridine conc.)i) Cu(II) = 30 μg/cm3

ii) 2’,4’-dinitro APTPT = 1 x 10-4 to 35 x 10-4 Miii) Pyridine = 5 cm3 of 0.5 Miv) pH = 8.0 and 8.5,v) Shaking time = 15 minvi) λmax = 445 and 645 nm vii) Blank = Reagent

i) Cu(II) = 30 μg/cm3

ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.5 M iii) Pyridine = 1 x 10-4 to 35 x 10-4 Miv) pH = 8.0 and 8.5,v) Shaking time = 15 minvi) λmax = 445 and 645 nm vii) Blank = Reagent

1) Slope ratio method (Fixed reagent conc.)

-2.5-2

-1.5-1

-0.50

0.51

1.52

-2.5 -2 -1.5 -1 -0.5 0Log C [Pyridine]

Absorbance

Ab.at 645 nm without Py

Ab. at 445 nm without Py

Ab. at 645 nm with py

Ab. at 445 nm with Py

1.81 1.83 1.78

1.66

34

00.020.040.060.080.10.120.140.16

0 0.2 0.4 0.6 0.8 1M / M + L

Absorbance

At445 nmAt 645 nmAt 445 nmAt 645 nm

i) Cu (II) = 50 μg/cm3

ii) 2’,4’-dinitro APTPT = 7.868 X 10-3 M

iii) Pyridine = 7.868 X 10-3 M iv) pH = 9.5v) Shaking time = 15 minvi) λmax = 445 nm and 645 nmvii) Blank = Reagent

2) Job’s method of continuous variation

III) Mole Ratio Method i) Cu (II) = 50 μg/cm3

ii) 2’,4’-dinitro APTPT = 7.868 X 10-3 Miii) Pyridine = 7.868 X 10-3 M iv) pH = 9.5v) Shaking time = 15 minvi) λmax = 445 nm and 645 nmvii) Blank = Reagent

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

0 0.5 1 1.5 2M / L

Absorbance

Ab. at 445 nm with PyAb. at 645 nm with Py.Ab. at 445 nm without Py.Ab. at 645 nm without Py.

35

The reactions of copper(II) with the reagent and pyridine, represented as follows by the equation

STRUCTURE

[Cu(H2O)4]2+ aq. + 2 R-SH org. [Cu(H2O)2 (R-S)2] org.+ 2H + + 2H20

[Cu(H2O)2 (R-S)2] org. + 2 Py org. [Cu(Py)2 (R-S)2] org. + 2H20 AdductStructure of Cu(II)- 2’,4’-dinitro APTPT-

pyridine complex

R S Cu S R

Py

PyN

N

CH3

CH3CH3

NH

O2N

NO2

= R

36

Characteristics of Method

1) Solvent :- Chloroform

2) λmax :- 445 nm and 645 nm

3) pH range :- 8.7-10.3 (9.5)

4) Reagent required for complete complexation :- 5 cm3

(0.01M)5) Pyridine required for complete complexation :- 5 cm3

(0.5M)6) Equilibrium time :-

15 min7) Stability of coloured complex :- > 48 8)Beer’s law range :- 10-

80 μg/cm3 9) Ringbom’s range : 20-60 μg/cm3

10) Molar absorptivity :- 0.873 x 103 dm3 mol-1 cm-1

11) Sandell’s sensitivity :- 0.072 μg cm-1

12) Stoichiometry (M:L:Py) :-1:2:2

Diverse ions Added as Amount tolerated(mg mL-1)

Masking agent

Cr(VI) K2Cr2O7 10.0Se(IV) SeO2 10.0Mn(II) MnCl2.6H2O 5.0Zn(II) ZnSO4.7H2O 5.0Mo(VI) (NH4)6Mo7O24.2H2O 5.0Ga(III) GaCl3 5.0Sn(IV) SnCl4 5.0Pb(II) Pb(NO3)2 5.0Fe(II) Fe(SO4)2.7H2O 3.0Y(III) Y(NO3)3 3.0Sn(II) SnCl2.2H2O 3.0Bi(III) Bi(NO3)3.5H20 3.0Te(IV) Na2TeO3 3.0Cr(III) CrCl3 1.0Mn(VII) KMnO4 1.0Ru(III) RuCl3.6H20 1.0Al(III) AlCl3.6H2O 1.0

Study of Diverse Ions

In(III) InCl3.4H2O 1.0Sb(III) Sb2O3 1.0Os(VIII) OsO4 1.0Ir(III) IrCl3.xH2O 1.0Au(III) HAuCl4 0.5 20.0 mg

thiosulphateAg(I) AgNO3 0.5 20.0 mg

thiosulphatePd(II) PdCl2 0.5 20.0 mg tartarateHg(II) HgCl2 0.5 5.0 mg

thiocyanateCo(II) CoCl2.6H2O 0.5 5.0 mg

thiocyanate Ni(II) NiCl2.6H20 0.5 5.0 mg

thiocyanate Cd(II) Cd(NO3)2.2H2O 0.5 5.0 mg

thiocyanate Iodide NaI 20.0Bromide KBr 20.0Nitrate NaNO3 20.0Nitrite NaNO2 20.0Thiosulphate Na2S2O3 20.0Tartarate C2H2O6 20.0Phosphate Na3PO4 5.0Sulphate K2SO4 5.0Malonate C3H3O4 5.0Thiocyanate NH4SCN 5.0Thiourea CS(NH2)2 5.0Oxalate Na2C2O4.2H2O 5.0

39

APPLICATIONS1) Separation of copper(II) from commonly associated metal ions Metal ion Amount taken, μg Average recovery,*%

R.S.D.,% Chromogenic ligand

Cu(II) 300 99.9 0.11Au(III) 100 99.9 0.09 2’,4’-Dinitro APTPTCu(II) 300 99.9 0.14Co(II)a 500 99.9 0.05 ThiocyanateCu(II) 300 99.9 0.08Ru(III) 200 99.7 0.21 ThioureaCu(II) 300 99.9 0.10Pd(II)b 100 99.8 0.13 4’-Chloro PTPTCu(II) 300 99.8 0.03Zn(II) 100 99.2 0.08 PARCu(II) 300 99.9 0.44Ni(II)a 100 99.4 0.76 DMGCu(II) 300 99.7 0.07Sn(IV) 100 99.8 0.14 Pyrocatechol violetCu(II) 300 99.8 0.10Cd(II)a 100 99.8 0.16 PARCu(II) 300 99.8 0.13Mn(II)a 100 99.9 0.06 PARCu(II) 300 99.9 0.09Fe(III) 50 99.7 0.28 ThiocyanateCu(II) 300 99.8 0.08Hg(II)a 100 99.7 0.25 PARCu(II) 300 99.9 0.20Pb(II) 100 99.8 0.10 PAR

40

2. Determination of copper(II) in a synthetic mixtures.Composition, μg Recovery*,

%R.S.D., %

Cu(II), 300; Fe(III), 50; Ni(II)a, 100

99.8 0.13

Cu(II), 300; Ni(II)a, 100; Pb(II), 100

99.9 0.07

Cu(II), 300; Pb(II), 100; Sn(IV), 100

99.8 0.12

Cu(II), 300; Zn(II), 100; Sn(IV), 100

99.9 0.05

Cu(II), 300; Ni(II)a, 100; Mn(II)a, 100

99.8 0.14

Cu(II), 300; Au(III), 100; Ni(II)a, 100

99.9 0.05

Cu(II), 300; Co(II)a, 500; Pb(II), 100

99.8 0.10

Cu(II), 300; Bi(III), 100; Cd(II)a, 100

99.8 0.15

Cu(II), 300; Fe(III), 50; Co(II)a, 500

99.7 0.20

Cu(II), 300; Ag(I)b, 300; Au(III), 100

99.8 0.12

Cu(II), 300; Zn(II), 100; Pb(II), 100

99.8 0.19

Cu(II), 300; Sn(IV), 100; Pb(II), 100

99.9 0.05

Cu(II), 300; Bi(III), 100; Sb(III), 100

99.9 0.07

* = Average of five determinations a = Masked with 5.0 mg thiocyanate b = Masked with 20.0 mg thiosulphate

41

3. Determination of copper(II) from alloysComposition of alloy,

%Certified values

of Cu(II)

,%

Amount of Cu(II) found*,

%

Confidence limitα = 0.95

R.S.D.%

AAS metho

d

proposed

method

Monel Metal (Shubh Chemi Incorporate, Mumbai)Mn, 13.50; Nia, 4.65; Fe, 0.68

80.1 80.1 80.1 0.20 0.52

Gun Metal (Kamini Industries supplied standards, India)Sn, 4.49; Sb, 0.31; Pb, 2.31

84.9 81.2 81.1 0.23 0.23

Brass(Shubh Chemi Incorporate, Mumbai)Zn, 41.90; Fe, 0.78; Mn, 0.55; Al, 0.51

56.2 54.8 54.7 0.03 0.05

Nickel-Silver (ITA, Laboratory, India)Nia, 17.00; Pb, 0.13; Sn, 0.05; Mn, 0.21

54.6 54.5 54.5 0.02 0.03

Copper-Silver (Locally prepared)Agb

, 66.7

33.3 30.1 30.1 0.02 0.06

•= Average of five determinations a = Masked with 5.0 mg thiocyanate

b = Masked with 20.0 mg thiosulphate

42

4. Determination of copper(II) from pharmaceutical allopathic samples

Allopathic sample

Composition

Certified

values of

Cu(II),

mg/tab

Amount of Cu(II) found* (

mg/tab)


R.S.D.,%.

proposed

method

AAS metho

d

Supradyn(Piramal Healthcare Ltd. Mahad)

Zinc sulphate 2.20 mg; Sodium molybdate dehydrate 0.25 mg; Sodium borate 0.88 mg; Magenesium oxide 6.0 mg; Calsium phosphate 129.0 mg; Ferrous sulphate 32.04 mg; Manganse sulphate monohydrate 2.03 mg

0.86

0.86 0.86

0.001 0.09

AO-7(Nicholas Piramal India Ltd. Mumbai)

Vit.A 300 i.u.; Vit.D 30 i.u.; Zinc oxide 40 mg; Manganese sulphate 5 mg; Sodium selenate 40 mg

1.59

1.56 1.57

0.02 1.27

Antoxid(Dr. Reddy’s Lab. Hyderabad)

Beta carotene 10 mg; Zinc sulphate monohydrate 200 mcg; Manganese sulphate 2.0 mg

0.25

0.25 0.25

0.005 1.92

Eldervit- ZC(Elder, Mumbai)

Vit.A 2500 i.u.; Vit C 150 mg; Vit. E 200 i.u.; Zinc 22.5 mg; Selenium 40 mcg

0.40

0.39 0.39

0.007 1.62

Divit(Franco-Indian Pharmaceuticals Pvt. Ltd.Mumbai)

Zinc oxide 24.89 mg; Selenium acid 0.114 mg; Chromium chloride 0.152 mg; Magnesiun oxide 66.32 mg; Manganese sulphate 6.152 mg; Calcium phosphate72.0 mg; Vit.A Palmitate 20.942 mg; Vit.B1 4.5 mg; Vit.B 2 5.0 mg; Vit.B3 400 mg; Vit.B6 1.5 mg; Vit.B12 mg; Vit.C 75 mg

0.13

0.12 0.12

0.002 1.36

43

5. Determination of copper(II) from ayurvedic samples

Name of ayurvedic medicine§

Composition,mg

Certified

values of

Cu(II), mg/gm

Amount of Cu(II) found*

mg/gm


R.S.D.,%

Proposed

method

AAS metho

d

Arogyavardhini Rasa

Fe, 3.4 34.0 33.8 33.7 0.23 0.18

Chandrakala Rasa

Hg a, 4.0 ; S, 1.0

40.0 39.4 39.5 0.24 0.20

Vatvidhanwas Rasa

Hg a, 7.0 ; S, 7.0 ; Fe, 7.0

70.0 69.7 69.6 0.14 0.12

Sootshekhar Rasa

Hg a, 7.0 ; S, 7.0

70.0 69.8 69.9 0.19 0.16•= Average of five determinations a = Masked with 5.0 mg thiocyanate § = Bhardwadja ayurvedic company, Amrutsar, India.

44

6. Determination of copper(II) from biological samples.

Botanical samples§

Amount found by proposed method*, mg/Kg

Amount found by AAS,mg/Kg


R.S.D.,%

Ambadi(Hibiscus cannabinus L.)

18.3 18.3 0.02 0.11

Roselle(Hibiscus sabdariffa L.)

14.0 14.0 0.03 0.18

Sea Hibiscus(Hibiscus tilaceus L.)

6.7 6.7 0.03 0.36

* = Average of five determinations § = Samples from Department of Botany, Shivaji university, Kolhapur

45

7. Determination of copper(II) from micronutrient fertilizer samples.

Fertilizer sample

Composition,%

Certified

values of

Cu(II),%

Amount of Cu(II) found*,

%

Confidence limit

α = 0.95

R.S.D.,%

proposed

method

AAS method

Multiplex(Karnataka Agro Chemicals, Bangalore, India)

Zn, 3.0; B, 0.5 ; Mo, 0.1; Mn 1.0; Fe, 2.5

1.0 1.0 0.97 0.04 3.26

Greenage(Chittari Agro Products, Kolhapur, India)

Fe, 2.5; Mn, 1.0; Zn, 3.0; Mo 0.1; B, 0.5

1.0 1.0 0.99 0.02 2.17

Agromax(Aeries Agro Limited, Bangalore, India)

Fe, 2.5; Mn, 1.0; Zn, 3.0; Mo 0.1

1.0 1.0 0.98 0.03 2.62

Bordo(Apex Bio Sciences, Pune, India)

CaCO3, 1.0 1.0 1.0 1.00 0.03 2.39

Multimol(Multimol Micro fertilizers Industries, Malegaon MIDC, Sinnar, India)

Fe, 2.5; Zn, 3.0; Mn, 1.0; B, 0.5; Mo, 0.1

1.0 1.0 0.99 0.02 1.97

* = Average of five determinations

46

Sequential seperaration of copper(II) from gold(III)

Aqueous phase: 300 μg copper(II) + 100 μg gold(II), adjust the pH 9.5, water was added to make volume up to 25 mL Organic phase: 5.0 mL of 0.01 mol L-1 2’,4’-dinitro APTPT + 5.0 mL of 0.5 mol L-1 pyridine in chloroform.Equilibrium time: 15 min

Cu(II) + Au(III)

5.0 mL of 0.01 mol L-1 2’,4’-dinitro APTPT +5.0 mL of 0.5 mol L-1 pyridine in chloroform

pH = 9.5 Equilibrium time: 15

min

Aqueous phase

Au(III) Organic phase

Cu(II)- 2’,4’-dinitro APTPT-pyridine

Green colored complex(Measured at λmax 445 nm and

645 nm)(Recovery, 99.9 %)

pH = 2.2 Equilibrium

time:5 min

Aqueous phase

(Rejected)

Organic phaseAu(III)- 2’,4’-dinitro

APTPT-pyridineOrange-red colored complex (Measured at λmax 445 nm)

(Recovery, 99.9 %)

5.0 mL of 0.02 mol L-1 2’,4’-dinitro APTPT +5.0 mL of 0.5 mol L-1 pyridine in 1,2-dichloroethane

47

SENSITIVE AND SELECTIVE SYNERGISTIC EXTRACTIVE SPECTROPHOTOMETRIC DETERMINATION OF SILVER(I) USING 1-(2’,4’-DINITRO AMINOPHENYL)-4,4,6-TRIMETHYL-1,4-DIHYDROPYRIMIDINE-2-THIOL: ANALYSIS OF REAL SAMPLES

Impact Factor:2.072

48

EXPERIMENTAL SECTIONApparatus: Absorption measurements were carried out with an Elico digital spectrophotometer model CL-27 using 1 cm quartz cell. The pH values were determined with an Elico digital pH meter model LI-120.

Glass vessels were cleaned by soaking in acidified solutions of K2Cr2O7, followed by washing with soap water and rinsed two times with water.Reagents: Standard stock solution of silver(I) was prepared by dissolving 1.5747 g of Silver nitrate (Merck), in water. The solution was made up to one liter (1mg/mL) and standardized by titrimetrically by a known Mohr’s method. The working solutions were prepared by dilution the stock solution suitably with water. All other chemicals and solvents used were of analytical reagents grade. Double distilled water was used throughout the experiment.

49

GENERAL EXTRACTION AND DETERMINATION PROCEDURE FOR Ag(I)

An aliquot of the sample solution containing 5 μg/cm3 silver(I) solution was taken and pH was adjusted to 3.5 with dil. nitric acid and sodium hydroxide in 25 cm3 volume. The solution was transferred into a 125 cm3 separatory funnel and thoroughly mixed with 4.0 cm3 of a 0.01 M 2’,4’-dinitro APTPT and 3.0 cm3 of 0.5 M pyridine in chloroform for 5 min. The two phages were allowed

to separate and the organic layer having a orange-red colour was transferred to a 10 cm3 standard flask and made up to the mark with chloroform. The

absorbance of the organic phase was measured at 440 nm against reagent blank. Unknown amount of silver(I) was determined from the calibration graph prepared in the same manner.

50

An aliquot of the sample solution containing 5 μg/cm3 Ag(I)



Mixed with 4.0 cm3 of a 0.01 M 2’,4’-dinitro APTPT and 3.0 cm3 of 0.5 M pyridine in chloroformTwo phases were allowed to separate

Absorbance of the orange-red organic phase was measured at 440 nm against reagent blank


51

RESULTS AND DISCUSSIONS


00.20.40.60.81

1.2

330 380 430 480 530 580W avelength, nmAb

sorbance

Reagent at 415 nm

Ab. of coloured complexat 440 nm

A

B

(A) Absorption spectra of 2’,4’-dinitro APTPT vs. Chloroform blank:(B) Absorption spectra of Ag(I)-2’,4’-dinitro APTPT complex vs. 2’,4’- dinitro APTPT blank: i) Ag(I) = 5 μg/cm3, ii) 2’,4’-dinitro APTPT = 4 cm3 of 0.01 M, iii) pH =3.5, v) Pyridine = 3 cm3 of 0.5 M, v) Shaking time=5min, vi) Scan = 330 to 580 nm, vii) Blank = Reagent

52

2. Effect of pH

0

0.1

0.2

0.3

0.4

0.5

0.6

0 2 4 6 8 10 12 14pH

Absorbance

W ith pyW ithout py

i) Ag(I) = 5 μg/cm3


iii) pH = 2.7 to 4.3 (3.5)With pyridine absorbance = 0.525Without pyridine absorbance =

0.230iv) Pyridine = 3 cm3 of 0.5 M v) Shaking time = 5 min vi) λmax = 440 nm, vii) Blank =

Reagent

00.10.20.30.40.50.6

0 50 100 1502’,4’-dinitro APTPT conc x 10-5 M

Absorban

ce W ith pyW ithout py

3. Effect of 2’, 4’-dinitro APTPT

Concentration i) Ag(I) = 5 μg/cm3

ii) 2’,4’-dinitro APTPT = 0.0005 to 0.01 M ( 4 cm3 0.01 M)iii) Pyridine = 3 cm3 of 0.5 Miv) pH = 3.5v) Shaking time = 5 min, vi) λmax = 440 nm, vii) Blank = Reagent

53

4. Effect of Shaking Time

00.10.20.30.40.50.6

0 5 10 15 20 25 Shaking tim e, m in

Absorbance W ith py

W ithout py

i) Ag(I) = 5 μg/cm3 ii) 2’,4’-dinitro APTPT = 4 cm3 of 0.01M iii) Pyridine = 3 cm3 of 0.5 Miv) pH = 3.5 v) Shaking time = 0 sec to 20 min ( 5 min)vi) λmax = 440 nm, vii) Blank = Reagent

00.10.20.30.40.50.6

0 1 2 3 4 5 6Pyridine conc in cm -3 (0.5 M )

Absorbance W ith py

6. Effect of Concentration of Synergent i) Ag(I) = 5 μg/cm3

ii) 2’,4’-dinitro APTPT = 4 cm3 of 0.01 M iii) Pyridine = 0 to 5 cm3 of 0.5 M (3 cm3)iv) pH = 3.5 v) Shaking time = 5.0 min vi) λmax = 440 nm, vii) Blank = Reagent

54

7. Validity of Beer’s Law

0

0.2

0.4

0.6

0.8

1

1.2

0 2 4 6 8 10 12Ag(I), ppm

Absorbance

W ith pyi) Ag(I) = 1 to 11 μg/cm3 ii) 2’,4’-dinitro APTPT = 4 cm3 of 0.01 M iii) Pyridine = 3 cm3 of 0.5 M iv) pH = 3.5 v) Shaking time = 5 min vi) λmax = 440 nm, vii) Blank = Reagent

0

20

4060

80

1000 0.2 0.4 0.6 0.8 1 1.2

Log ppm, Ag(I)

Absorbance

At 440 nm with Pyi) Ag(I) = 3 to 10 μg/cm3 ii) 2’,4’-dinitro APTPT = 4 cm3 of 0.01 M iii) Pyridine = 3 cm3 of 0.5 M iv) pH = 3.5 v) Shaking time = 5 min vi) λmax = 440 nm, vii) Blank = Reagent

8. Ringboms plot for determination of

optimum concentration of Ag(I)

55

0

0.05

0.1

0.15

0.2

0 0.2 0.4 0.6 0.8 1M / M +L

Absorbance

W ith py W ithout pyIII) Job plot method

i) Ag(I) = 150 μgii) 2’,4’-dinitro APTPT = 9.27 x 10-4 Miii) Pyridine = 3 cm3 of 0.5 M iv) pH = 3.5 v) Shaking time = 5 min vi) λmax = 440 nmvi) Blank = Reagent

IV) Mole Ratio Method

0

0.05

0.1

0.15

0.2

0.25

0 0.5 1 1.5 2M / L

Absorbance

W ith py W ithout py

i) Ag(I) = 150 μgii) 2’,4’-dinitro APTPT = 9.27 x 10-4 Miii) Pyridine = 3 cm3 of 0.5 M iv) pH = 3.5 v) Shaking time = 5 min vi) λmax = 440 nmvi) Blank = Reagent

56


-1-0.8-0.6-0.4-0.20

0.20.40.60.81

1.2

-4.5 -4 -3.5 -3 -2.5 -2Log C [2’,4’-dinitro APTPT]

Log D

pH = 6.0 pH = 2.5

Slope = 0.94

Slope = 0.94

Slope Ratio Method: (Fixed pyridine conc.)

-0.8-0.6-0.4-0.20

0.20.40.60.8

-1.9 -1.6 -1.3 -1 -0.7 -0.4Log C [Pyridine]

Log D

pH = 6.0 pH = 2.5

Slope = 1.07

Slope = 1.1

Slope Ratio Method: (Fixed reagent conc.)i) Ag(I) = 5 μg/cm3 ii) 2’,4’-dinitro APTPT = 4 cm3 of 0.01 M iii) Pyridine = 1 x 10-4 to 35 x 10-4 M iv) pH = 6.0 and 2.5 v) Shaking time = 5 min vi) λmax = 440 nmvii) Blank = Reagent

i) Ag(I) = 5 μg/cm3 ii) 2’,4’-dinitro APTPT = 1 x 10-4 to 35 x 10-4 M iii) Pyridine = 3 cm3 of 0.5 Miv) pH = 6.0 and 2.5 v) Shaking time = 5 min vi) λmax = 440 nmvii) Blank = Reagent

57

As 2’,4’-dinitro APTPT is a weak organic acid, its degree of dissociation increases with decreasing acidity in the aqueous phase. At the given acidity, silver(I) reacts with 2’,4’-dinitro APTPT in the presence of auxiliary ligand pyridine, giving an uncharged chelate which is distributed between two phases according to the following equations

STRUCTURE

Ag+ + R – S H Ag-SR + H+ Ag-SR + Py Ag (Py) SR adduct

Based on this reaction, the probable structure of silver(I)-2’,4’-dinitro APTPT-pyridine complex is as shown in Fig.

NN

N

O2N

NO2

S

Ag PyH

58

Study of Diverse Ions

Ions added as Tolerance limit, mg

Cr(VI), Mn(II), sulphate, acetate 50

Ir(III), In(III), Tl(III), Se(IV), fluoride, nitrate, nitrite, EDTA, cirate

25

Bi(III), Te(IV), Al(III), Zn(II), Ge(III), Ni(II)a, phosphate

15

Mo(II), W(VI), Sn(II), Cd(II)a, Hg(II)a, Pd(II)a, malonate, salicylate

10

Cr(III), Sn(IV), Mg(II), Co(II)a, Mn(VII)a, ascorbate, oxalate, thiocynate

5

Sr(II), Y(III), Th(IV), Ca(II), Fe(II), Pb(II), Pt(IV), thiourea

3

Sb(III), Au(III)b, Ru(III), Fe(III), tartarate 1

Gd(III), Nb(V), U(VI), Zr(IV),Os(VIII), Rh(III)

0.500a Masked by 25 mg EDTA b Masked by 5 mg

Thiocynate

59

1. Binary separation of Ag(I) from associated metal ions Applications

Metal ion Amount taken, μg

Average recovery*,

%R.S.D., % Chromogenic

ligand

Ag(I) 50 99.9 0.09Au(III)a 100 99.8 0.05 2’,4’-Dinitro

APTPTAg(I) 50 99.9 0.13Pt(IV) 300 99.9 0.09 SnCl2Ag(I) 50 99.9 0.14Ru(III) 200 99.7 0.20 ThioureaAg(I) 50 99.9 0.08Ni(II)b 75 99.8 0.15 DMGAg(I) 50 99.9 0.11Mn(II) 100 99.9 0.09 PARAg(I) 50 99.8 0.09Zn(II) 100 99.7 0.08 PARAg(I) 50 99.9 0.12Hg(II)b 100 99.9 0.19 PARAg(I) 50 99.9 0.14Cd(II)b 100 99.9 0.09 PARAg(I) 50 99.8 0.08Cu(II)b 1000 99.9 0.12 4’-Chloro PTPTAg(I) 50 99.8 0.08Pd(II)b 100 99.7 0.16 4’-Chloro PTPTAg(I) 50 99.8 0.21Co(II)b 500 99.9 0.07 Thiocynate

60

2. Determination of Ag(I) from ternary synthetic mixtures

Composition (μg) Average recovery*, %

R.S.D., %

Ag(I), 50; Cu(II), 300; Au(III)a, 100

99.9 0.09

Ag(I), 50; Au(III)a, 100; Pt(IV), 300

99.9 0.12

Ag(I), 50; Cu(II)b, 1000; Pd(II)b, 100

99.8 0.09

Ag(I), 50; Ni(II)b, 75; Pb(II), 100

99.7 0.18

Ag(I), 50; Cu(II)b, 1000; Sn(IV), 75

99.8 0.13

Ag(I), 50; Zn(II), 100; Mn(II)b, 100

99.9 0.15

Ag(I), 50; Co(II)b, 100; Cu(II)b, 1000

99.8 0.09

Ag(I), 50; Bi(III), 100; Cd(II)c, 100

99.8 0.09

Ag(I), 50; Hg(II)b, 100; Ru(III), 100

99.9 0.09

Ag(I), 50; Pt(IV), 300; Os(VIII), 200

99.9 0.17

Ag(I), 50; Sn(IV), 100; Bi(III), 100

99.9 0.10

Ag(I), 50; Ru(III), 100; Ir(III), 100

99.9 0.09

Ag(I), 50; Au(III)b, 100; Pd(II)b, 100

99.9 0.09

* Average of five determinations a Masked with 5 mg Thiocynate b Masked by 25 mg EDTA

61

3. Determination of Ag(I) from ayurvedic sample

Ayurvedic medicine

Certified value of Ag(I) mg/gm

Amount of Ag(I) found* mg/gm


R.S.D., %Propose

d method

AAS method

Siddhayoga Kalpa 1.00 0.98 1.00 0.019 0.016

Roupya Suvarna Sootshekharb

7.35 7.34 7.34 0.82 0.09

Vishtinduk Vatic 24.67 24.66 24.65 0.45 0.015

* Average of five determinations a Shree Bhuvaneshwari, Aushadhashram,Gondal, Gujrat, India.b Aushadhi Bhavan, Ayurved seva sangha, Panchawati, Nashik, Maharashtra, India.c Dorle Ayurved, Kolhapur, Maharashtra, India.

62

4. Determination of Ag(I) from silver deposited thin films and silver nano powder

Silver nano materials Amount of Ag(I) found* mg/gm

Confidence

limitα = 0.95

R.S.D., %

Proposed method

AAS metho

d

Sample No. 1a 248.3 248.4 1.84 0.006

Sample No. 2a 309.1 309.1 1.91 0.005

Sample No. 3a 341.0 341.1 2.96 0.007

Sample No. 4a 300.0 300.2 1.11 0.003

Silver nano powderb 39.0 39.1 0.38 0.008

Silver copper nanocomposite powderb

68.0 68.2 0.42 0.005

* Average of five determinations a Silver deposited thin film, Department of Physics, Shivaji University, Kolhapur, India b Department of Physics, Shivaji University, Kolhapur, India.

63

5. Determination of Ag(I) from hypo solution and waste refinery effluent water.

Hypo solution/ waste effluent water

Amount of Ag(I) found* mg L-1


R.S.D., %Proposed

methodAAS

method

Sample No.1a 11.4 11.3 0.042 0.003

Sample No.2b 13.6 13.7 0.26 0.016

Sample No. 3c 8.2 8.4 0.07 0.007

Sample No. 4c 9.4 9.5 0.018 0.016

Sample No. 5c 7.4 7.4 0.08 0.009

Sample No. 6c 6.8 6.9 0.110 0.013

* Average of five determinationsa Chatrapati Shahu Maharaja Government Medical College and C.P.R. Hospital, Kolhapur, India.b Dr. D. Y. Patil Medical College and Hospital, Kolhapur, India.c Waste effluent water from silver refinery, Hupari-Yalgud, Kolhapur, India.

64

SELECTIVE SYNERGISTIC EXTRACTION AND SPECTROPHOTOMETRIC DETERMINATION OF GOLD(III) WITH 1-(2’,4’-DINITRO AMINOPHENYL)-4,4,6-TRIMETHYL-1,4-DIHYDROPYRIMIDINE-2-THIOL

Impact Factor:3.722

65

Experimental

Apparatus: Absorption measurements were carried out with an Elico digital spectrophotometer model CL-27 using 1 cm quartz cell. The pH values were determined with an Elico digital pH meter model LI-120.

Glass vessels were cleaned by soaking in acidified solutions of K2Cr2O7, followed by washing with soap water and rinsed two times with water.Reagents:Standard gold(III) solution:A stock solution of gold (III) was prepared by dissolving an accurately weighed amount of HAuCl4 (Johnson Mathey, Ltd UK) in 250 mL of double-distilled water with a few drops of concentrated hydrochloric acid and standardized by a known gravimetric method.

66

General Extraction Procedure

An aliquot of the sample solution containing 10 μg/cm3 Au(III)



Mixed with 5.0 cm3 of a 0.02 M 2’,4’-dinitro APTPT and 5.0 cm3 of 0.5 M pyridine in 1,2 dichloroethane

Two phases were allowed to separate

Absorbance of the orange-red organic phase was measured

at 445 nm against reagent blank


67

RESULTS AND DISCUSSIONS


00.1

0.20.30.40.5

0.60.70.8

0.91

200 250 300 350 400 450 500 550 600W avelength, nm

Absorbance

Reagent at 415 nm

Coloured complex at 445 nm

A

B

(A) Absorption spectra of 2’,4’-dinitro APTPT vs. 1, 2dichloroethane blank:(B) Absorption spectra of Au(III)-2’,4’-dinitroAPTPT-pyridine complex vs. 2’,4’- dinitro APTPT blank: i) Au(III) = 10 μg/cm3, ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.02 M, iii) pH = 2.2, v) Pyridine = 5 cm3 of 0.5 M, v) shaking time= 5 min, vi) Scan = 300 to 800 nm, vii) Blank = Reagent

68

2. Effect of pH

i) Au(III) = 10 μg/cm3


iii) pH = 1.7 to 2.4 (2.2)iv) Pyridine = 5 cm3 of 0.5 M v) Shaking time = 10 min vi) λmax = 445, Blank =

Reagent

0

0.1

0.2

0.3

0.4

0.5

0 2 4 6 8 10 12pH

Absorbance

W ith pyW ithout py

00.050.10.150.20.250.30.350.40.450.5

0 20 40 60 80 100Reagent concentration x 10-4

Absorbance

W ith pyridine

W ith 3-picoline

W ith 4-picoline

W ithout pyridine, 3-picoline and 4-picoline

3. Effect of 2’, 4’-dinitro APTPT Concentration i) Au(III) = 10 μg/cm3

ii) 2’,4’-dinitro APTPT = 0.0005 to 0.01 M ( 5.0 ml of 0.02 M)iii) Pyridine = 5 cm3 of 0.5 Miv) pH = 2.2v) Shaking time = 5 min, vi) λmax = 445 vii) Blank = Reagent

69

4. Effect of Shaking

Time

5. Effect of Concentration of

Synergent

00.050.10.150.20.250.30.350.40.45

0 2 4 6 8 10 12Equilibrium time, min

Absorbance

W ith pyridineW ithout pyridine

0

0.1

0.2

0.3

0.4

0.5

0 1 2 3 4 5Pyridine and picoline concentration, cm -3 (0.5 m ol L-1)

Absorbance

W ith pyridine at 445 nm W ith picoline at 445 nmi) Au(III) = 10 μg/cm3

ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.02 M iii) Pyridine = 0 to 5 cm3 of 0.5 M (5 cm3)iv) pH = 2.2 v) Shaking time = 5 min vi) λmax = 445 vii) Blank = Reagent

i) Au(III) = 10 μg/cm3 ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.02 M iii) Pyridine = 5 cm3 of 0.5 Miv) pH = 2.2v) Shaking time = 0 sec to 20 min (5 min)vi) λmax = 445 nm vii) Blank = Reagent

70

6. Validity of Beer’s Law

00.1

0.20.30.40.5

0.60.70.8

0.91

0 50 100 150 200 250 300Au(III), ppm

Absorbance

at 445 nm0102030405060708090

0 0.5 1 1.5 2 2.5 3Log ppm, [Au(III)]% Transmittance

At 445 nm

7. Ringbom’s plot for

determination of optimum

concentration of Au(III)

i) Au(III) = 2.5 to 25 μg/cm3 ii) 2’,4’-dinitro APTPT = 5 cm3 of 0.02 M iii) Pyridine = 5 cm3 of 0.5 M iv) pH = 2.2v) Shaking time = 5 min vi) λmax = 445 nmvii) Blank = Reagent viii) Optimum range 5 to 20 μg/cm3

71


Slope Ratio Method: (Fixed Reagent conc.)

Slope Ratio Method: (Fixed Pyridine conc.)

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

-4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0Log C [2’,4’-dinitro APTPT]

Log D

[Au(III)]

pH 3.2pH 1.6

Slope = 0.78

Slope = 0.75

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

-2 -1.5 -1 -0.5 0Log C [Pyridine]

Log D

[Au(II

I)]

PH 3.2pH 1.6

Slope = 0.98

Slope = 1.02


ii) 2’,4’-dinitro APTPT = 2 x 10-4 to 7 x 10-4 Miii) Pyridine = 5 cm3 of 0.5 M iv) pH =3.2 and 1.6 v) Shaking time = 5 minvi) λmax = 445 nmvii) Blank = Reagent


ii) 2’,4’-dinitro APTPT = 5 cm3

of 0.02 M iii) Pyridine = 2.5 x 10-3 to 25 x 10-3 iv) pH =3.2 and 1.6 v) Shaking time = 5 minvi) λmax = 445 nmvii) Blank = Reagent

72

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 0.5 1 1.5 2 M / L

Absorbance


0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0 0.2 0.4 0.6 0.8 1M / M + L

Absorban

ce


IV) Job plot method

III) Mole Ratio Method: i) Au(III) = 30 μg/cm3

ii) 2’,4’-dinitro APTPT = 1.523 X 10-3 Miii) Pyridine = 1.523 X 10-3 Miv) pH = 2.2v) Shaking time = 5 minvi) λmax = 445 nmvii) Blank = Reagenti) Au(III) = 30 μg/cm3

ii) 2’,4’-dinitro APTPT = 1.523 X 10-3 Miii) Pyridine = 1.523 X 10-3 Miv) pH = 2.2v) Shaking time = 5 minvi) λmax = 445 nmvii) Blank = Reagent

73

HAuIIICl4 + 3 R – S H AuISR + R-S-S-R + 4 HCl

AuISR + Py Au (Py) SR adduct

Gold(III) reacts with 2’,4’-dinitro APTPT in the presence of auxiliary ligand pyridine, giving an uncharged chelate which is distributed between two phases according to the following equations,

Structure

74

Coexisting ions

Added asAmount tolerated(mg)

Without masking agent

absorbance at 445

nm

With masking agent absorbance at 445 nm

Maskng agent

None - - 0.424Zn(II) ZnSO4.7H2O 25.0 0.424Mn(II) MnCl2.6H2O 25.0 0.424Sn(II) SnCl2.2H2O 25.0 0.424Al(III) AlCl3.6H2O 25.0 0.424Tl(I) TlNO3 25.0 0.424Te(IV) Na2TeO3 25.0 0.424Ca(II) CaCO3 25.0 0.424Ce(IV) Ce(SO4)2 25.0 0.424Se(IV) SeO2 15.0 0.424Ga(III) GaCl3 10.0 0.424Mo(VI) (NH4)6Mo7O24.2H2O 10.0 0.424Fe(III) (NH4)Fe(SO4)2.12H2O 5.0 0.424Ir(III) IrCl3.xH2O 5.0 0.424Y(III) Y(NO3)3 5.0 0.424Cr(III) CrCl3 3.0 0.424Sn(IV) SnCl4 3.0 0.424In(III) InCl3.4H2O 3.0 0.424Sr(II) Sr(NO3)2 3.0 0.424Ba(II) BaCl2.2H2O 3.0 0.424Gd(III) Gd2O3 3.0 0.424Th(IV) Th(NO3)4 3.0 0.424Mg(II) MgCl2.6H2O 3.0 0.424Fe(II) Fe(SO4)2.7H2O 1.0 0.424

Influence of foreign ions

75

Co(II) CoCl2.6H2O 5.0 0.932 0.424 5 mg NH4SCNPb(II) Pb(NO3)2 5.0 0.236 0.424 5 mg Na2EDTACd(II) Cd(NO3)2.2H2O 5.0 1.532 0.424 5 mg Na2EDTASb(III) Sb2O3 5.0 0.172 0.424 5 mg Na2EDTAOs(VIII) OsO4 1.0 0.023 0.424 5 mg NH4SCNCu(II) CuSO4.5H2O 1.0 1.321 0.424 5 mg Na2EDTAMn(VII) KMnO4 1.0 0.186 0.424 5 mg Na2EDTABi(III) Bi(NO3)3.5H20 1.0 0.182 0.424 100 mg

Na3C6H5O7

Iodide NaI 100 0.424Citrate Na3C6H5O7 100 0.424Sulphate K2SO4 100 0.424Tartarate C2H2O6 100 0.424Bromide KBr 50 0.424Phosphate Na3PO4 50 0.424Malonate C3H3O4 50 0.424Fluoride NaF 25 0.424Nitrate NaNO3 25 0.424Acetate CH3COONa 25 0.424Thiourea CS(NH2)2 5 0.424EDTA Na2EDTA 5 0.424Thiocynate NH4SCN 5 0.424Nitrite NaNO2 1 0.424

76

1. Separation of gold(III) from Associated Metals

Metal ion Amount taken, μg

Average % Recovery*

R.S.D.%

Chromogenic ligand

Au(III) 100 99.9 0.09Cu(II)a 1000 99.8 0.17 4’-chloro PTPTAu(III) 100 99.9 0.10Co(II)b 500 99.9 0.05 ThiocyanateAu(III) 100 99.8 0.24

Os(VIII)b 500 99.8 0.15 ThioureaAu(III) 100 99.7 0.27Pt(IV) 300 99.9 0.09 SnCl2Au(III) 100 99.8 0.20Sb(III) 250 98.7 1.32 Ascorbic acid

+ KIAu(III) 100 99.9 0.06Ru(III) 200 99.6 0.42 ThioureaAu(III) 100 99.7 0.23

Ir(III)150 99.6 0.41 HBr + SnCl2

Au(III) 100 99.7 0.30Bi(III)c 100 99.6 0.37 Ascorbic acid

+ KIAu(III) 100 99.9 0.15Pd(II)a 100 99.7 0.26 4’-chloro PTPTAu(III) 100 99.8 0.15Hg(II)a 100 99.9 0.07 PARAu(III) 100 99.5 0.49Ni(II)b 75 98.4 1.51 DMGAu(III) 100 99.8 0.22Fe(III) 50 98.6 1.39 Thiocyanate

77

2. Determination of gold(III) in a Synthetic Mixtures

Composition,μg

Average % Recovery*

R.S.D.%

Au, 100; Pda 100; Pt, 300 99.9 0.14

Au, 100; Cua,1000; Hga, 100 99.8 0.18

Au, 100; Bic, 100; Fe,200 99.8 0.15

Au, 100; Ru, 200; Osb,200 99.8 0.17

Au, 100; Nib, 1000; Hga, 100

99.8 0.20

Au, 100; Sbd,50; Ru, 100 99.9 0.14

Au, 100; Cob, 500; Nib, 1000

99.5 0.50

Au, 100; Ir, 200; Pt, 300 99.8 0.21

Au, 100; Age, 100; Pt, 300 99.8 0.20

Au, 100; Age, 100; Cua, 1000

99.9 0.10* = Average of five determinations a = Masked with 5 mg EDTA

b = Masked with 5 mg thiocyanate c = Masked with 100 mg citrate

d = Masked with 25 mg flouride e = Precipitate out by 10 M HCl (10 cm3)

78

3. Determination of gold(III) from Ayurvedic Samples

Name of Medicine Certified

value of

gold(III)

mg/gm

Amount found by

AAS, mg/gm

Amount found by

proposed

method*, mg/gm


R.S.D.%

Vasantkumar Rasa 26.1 25.25 24.72 0.068 0.20Brahatshwas Kas Cintamani Rasa

72.1 69.15 69.15 0.086 0.09

Garbhcintamani Rasa (Brihat)

14.0 13.82 13.82 0.040 0.24

Brahmi Vati 3.0 3.10 3.10 0.001 0.03Makardhwaja Vati 1.0 1.24 1.22 0.002 0.12

79

Sequential seperaration of copper(II), silver(I) and gold(III)Aqueous phase: 300 μg copper(II) + 50 μg silver(I) + 100 μg gold(III) + 1.0 mL of 5 mg mL-1 Thiocynate, adjust the pH 3.5, in a total volume of 25 mL

Ag(I) + Cu(II) + Au(III)pH = 3.5

Aqueous phaseCu(II) + Au(III)

Organic phaseAg(I)-2’,4’-dinitro APTPT-pyridine Orange-red colored complex (Measured at λmax 440 nm), (Recovery, 99.9 %) *

5.0 mL of 0.01 mol L-1 2’,4’-dinitro APTPT + 5.0 mL of 0.5 mol L-1 pyridine in chloroform

pH = 9.5Equilibrium time:

15 min

Aqueous phase

Au(III)

Organic phaseCu(II)-2’,4’-dinitro APTPT-pyridine, Green colored complex, (Measured at λmax 445 nm and 645 nm), (Recovery, 99.9 %) **pH = 2.2

Equilibrium time: 5 min

Demasked with conc. HClO45.0 mL of 0.02 mol L-1 2’,4’-dinitro APTPT + 5.0 mL of 0.5 mol L-1 pyridine in 1, 2-dichloroetane

Aqueous phaseRejected

Organic phaseAu(III)-2’,4’-dinitro APTPT-pyridine, Orange-red colored complex, (Measured at λmax 445 nm), (Recovery, 99.9 %) ***

4.0 mL of 0.01 mol L-1 2’,4’-dinitro APTPT + 3.0 mL of 0.5 mol L-1 pyridine + 3.0 mL chloroform to make total volume 10 mL, Equilibrium time: 5 min

* Ind. Eng. Chem. Res. 2011, 50, 11270-11279 (Am. Chem. Soc.)** Spectrochem. Acta Part A, 78 (2011) 1455-1466 (Elsevier)*** Talanta, 81 (2010) 1088-1095 (Elsevier)

1. Easily synthesized the 2’,4’-dinitro APTPT chromogenic extractant in laboratory.

2. Low reagent concentration is required for quantitative determination of transition metal ions.

3. The extraction procedure is a single stage therefore to avoid the loss solvents.

4. Pyridine used as a auxiliary synergent for effectively extraction.

5.Extraction procedure is free from interference of a large number of foreign ions which are associated with Copper(II), Silver(I) and Gold(III) in its natural occurrence.

6.The selectivity was enhanced by the use of suitable masking agents.

7. 2’,4’-Dinitro APTPT reagent used for group separation of coinage metal ions.

8. Reliability of the procedures tested by carrying analysis of synthetic mixtures and real sample.

9. The developed methods are simple, rapid, reliable and reproducible used for separation and determination of Copper(II), Silver(I) and Gold(III).

RESEARCH HIGHLIGHTS

81

PUBLICATIONS

82

83

Dr. Lokhande T. N. Dr. Kokekar G. B.

Dr. Rajmane M. M. Dr. Kolekar S. S.

Dr. Sargar B. M Dr. Shilimkar T. N.

Dr. Gaikwad S. H. Mrs. Wagh R.D.

Mr. Motagi A.S. Dr. Mahamuni S.V.

Dr. Mane C. P. Dr. Kokare B.N.

Dr. Kamble G. S. Dr. Mandhare A. M.

Mr. D. P. Waghmode Mr. M. D. Jamdar

Mr. S. P. Jagtap Mr. Zanje

Mrs. A. P. Gaikwad Mrs. L. E. Noronha

Anantapur, AP ppt

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