Journal Name: Food Chemistry Supplementary material for: Rapid analysis of tristyrylphenol ethoxylates in cucumber- field system using supercritical fluid chromatography- tandem mass spectrometry Zejun Jiang a,b , Xiaolin Cao a,b , Hui Li a,b , Chan Zhang a,b , A. M. Abd El- Aty c , Ji Hoon Jeong d , Yong Shao a,b , Hua Shao a,b , Maojun Jin a,b , Fen Jin a,b, *, Jing Wang a,b, * a Key Laboratory of Agro-product Quality and Safety, Institute of Quality Standard & Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China b Key Laboratory of Agri-food Safety and Quality, Ministry of Agriculture of China, Beijing 100081, P. R. China -S1- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2
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ars.els-cdn.com · Web viewTypical chromatograms of (A) blank cucumber sample, (B) cucumber spiked at 0.1 mg kg−1, (C) blank leaves sample, (D) leaves spiked at 0.1 mg kg−1, (E)
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Journal Name: Food Chemistry
Supplementary material for:
Rapid analysis of tristyrylphenol ethoxylates in cucumber-field system using
supercritical fluid chromatography-tandem mass spectrometry
Zejun Jianga,b, Xiaolin Caoa,b, Hui Lia,b, Chan Zhanga,b, A. M. Abd El-Atyc, Ji Hoon Jeongd,
a Key Laboratory of Agro-product Quality and Safety, Institute of Quality Standard & Testing
Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R.
Chinab Key Laboratory of Agri-food Safety and Quality, Ministry of Agriculture of China, Beijing 100081,
P. R. Chinac Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, 12211 Giza, Egyptd Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, Republic of
Text S1. Purification and characterization of TSPxEOs standard
Agricultural emulsifier 601# (AE-601, generously gifted by Jiangsu Zhongshan Chemical Co.,
Ltd., Nanjing, Jiangsu, China) was used as the source for TSPxEOs, which are not commercially
available as reference substances. This product is a technical mixture of homologues with different
numbers of styrene and ethoxylate units (Fig. S1). The main components were identified by liquid
chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry (LC-ESI-Q-
TOF-MS). The full scan mass spectrum of AE-601 (Fig. S2) obtained by LC-ESI-TOF-MS displayed
several series of signals with almost Gaussian-shaped distributions characteristic pattern. Same as
other ethoxylated surfactants, the mass differences of 44.02 Da or 22.01 Da were observed in
neighboring oligomers in AE-601, which correspond to single- and double-charged ethylene oxide
group. All ions were dominated by ammonium adduct ions ([M + NH4]+ or [M + 2NH4]2+). As a
result, the three most homologous series of oligomers in AE-601 were named as TSPxEOs,
distyrylphenol ethoxylates (DSPxEOs), and tetrastyrylphenol ethoxylates (TeSPxEOs). Because
DSPxEOs and TeSPxEOs were relatively low in abundance; TSPxEOs was used for further
experimental work throughout the MS
For quantitative analysis, TSPxEOs, the main component in AE-601, was prepared by purifying
AE-601 using preparative liquid chromatography. The purified TSPxEOs was used as reference
standards. Fig. S3 provides a chromatographic comparison of AE-601 before and after purification.
Subsequently, the ethoxymer distribution of the purified TSPxEOs standard was determined using
the molar absorption coefficient technique proposed by Wang & Fingas (1993) and the theoretical
calculation technique proposed by Michel, Brauch, Worch, & Lange (2012). The molar absorption
coefficient technique was obtained based on the assumption that the molar response factors of
individual oligomers of ethoxylated surfactants are independent from the length of the ethoxylate
chain and rather constant (Ciofi et al., 2016; Wang et al., 1993). Whereas, the theoretical calculation
applied for characterization of trisiloxane surfactants (Michel et al., 2012) and alkylphenol
ethoxylates (Jiang et al., 2017)
The percentage composition of individual oligomers of TSPxEOs obtained by both approaches
are presented in Fig. S4. The observed distributions are represented by normalizing the mass fraction
summation of all fractions equivalent to 1. The results obtained by theoretical and experimental
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approaches in Fig. S4 have shown the percentage distribution of TSPxEOs (x = 6–27) were rather
similar in shape and were centered at x = 16, which indicates a good agreement between the two
models.
Data representing the percentage composition of oligomers with x <5 and x >27 cannot be
measured by a molar absorption coefficient technique, owing to the fact that oligomers with x <5
were not well resolved from each other and those with x >27 were quite low in abundance.
Individual concentrations of TSPxEOs oligomers (x = 1–5, and x = 30) obtained by theoretical
calculation might not be close to reality. Consequently, further method development (quantitative
analysis) was limited to 6 ≤ x≤ 29 and the percentage distribution of the purified TSPxEOs standards
(6 ≤ x≤ 29) obtained by theoretical calculation was used for quantitative analysis throughout the
study.
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Fig. S1. Chemical structure of tristylphenol ethoxylates (TSPxEOs).
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Fig. S2. The full scan mass spectrum of 2 mg mL−1 AE-601 using LC-ESI-Q-TOF-MS. Agilent 1290 series LC coupled to 6545 Q-TOF (Agilent Technologies, Waldbronn, Germany) equipped with electrospray Jet Stream Technology operating in positive ion mode under the following operation parameters: injection volume, 5 µL; flow rate, 0.3 mL min−1; column temperature, 40 °C; mobile phase, 10 mM CH3CHOONH4 in MeOH (isocratic); mass scanning range, 400-1600 m/z; acquisition rate, 0.6 spectra s−1; fragmentor voltage, 135 V; skimmer voltage, 65 V; octopole RF, 750 V; gas temperature, 320 °C; drying gas, 8 L min−1; nebulizer pressure, 35 psig; sheath gas flow, 11 L min−1; sheath gas temperature, 350 °C were used for identification.
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Fig. S3. Chromatographic comparisons of AE-601 before (upper panel) and after purification (lower panel). Chromatographic conditions were: Column, XBridge C18 column (2.1 mm i.d. × 150 mm, 3.5 µm, Waters, Ireland); column temperature, 25 °C; mobile phase( A), acetonitrile and mobile phase (B), water; flow rate, 0.2 mL min−1; injection volume, 10 μL; the gradient, 0–2 min, 20% A; 2–15 min, 20–95% A; 15–20 min, 95% A; 20–21 min, 95–20% A; 21–30 min, 20% A; detector, diode array detector (DAD); and detection wavelength, 224 nm.
Fig. S4. Comparison of percentage distribution of the purified TSPxEOs standard using theoretical
calculation and molar absorption coefficient method.
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Fig. S5. Cleanup performance using different sorbents. The scheme number for the given vials is the
same as reported in Table 2.
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-40
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40M
atri
x ef
fect
(%)
Number of ethoxylate units
Soil Cucumber Leaves
Fig. S6. Matrix effects (MEs) of TSPxEOs oligomers (x = 6–29) in cucumber, leaves, and soil.
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Fig. S7. Typical chromatograms of (A) blank cucumber sample, (B) cucumber spiked at 0.1 mg kg−1, (C) blank leaves sample, (D) leaves spiked at 0.1 mg kg−1, (E) blank soil, and (F) soil spiked sample at 0.1 mg kg−1. Peaks order are the same as shown in Fig. 2.
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Table S1. Molecular weight, retention time, adduct ion, and MS/MS parameters of the tested analytes.
Note: NI, not include in calibration curves, due to low abundances and sensitivity related issues.
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Table S3. Mean recoveries (%) and precision (intra-day RSDr and inter-day RSDR, %) of individual TSPxEOs oligomers (x = 6–29) in cucumber, leaves, and soil at
three fortification levels.
No. OligomerFortification level
(μg kg−1)
Cucumber Leaves Soil
Mean recoveries RSDr* RSDR
# Mean recoveries RSDr RSDR Mean recoveries RSDr RSDR
Ciofi, L., Ancillotti, C., Chiuminatto, U., Fibbi, D., Pasquini, B., Bruzzoniti, M. C., Rivoira, L., & Del Bubba, M. (2016). Fully automated on-line solid phase extraction coupled to liquid chromatography-tandem mass spectrometry for the simultaneous analysis of alkylphenol polyethoxylates and their carboxylic and phenolic metabolites in wastewater samples. Analytical and Bioanalytical Chemistry, 408(12), 3331-3347.
Jiang, Z.-J., Cao, X.-L., Li, H., Zhang, C., Abd El-Aty, A. M., Jin, F., Shao, H., Jin, M.-J., Wang, S.-S., She, Y.-X., & Wang, J. (2017). Fast determination of alkylphenol ethoxylates in leafy vegetables using a modified quick, easy, cheap, effective, rugged, and safe method and ultra-high performance supercritical fluid chromatography–tandem mass spectrometry. Journal of Chromatography A, 1525, 161-172.
Michel, A., Brauch, H. J., Worch, E., & Lange, F. T. (2012). Development of a liquid chromatography tandem mass spectrometry method for trace analysis of trisiloxane surfactants in the aqueous environment: an alternative strategy for quantification of ethoxylated surfactants. Journal of Chromatography A, 1245, 46-54.
Wang, Z., & Fingas, M. (1993). Rapid separation of non-ionic surfactants of polyethoxylated octylphenol and determination of ethylene oxide oligomer distribution by C1 column reversed-phase liquid chromatography. Journal of Chromatography A, 637(2), 145-156.