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Kong Y.,Jiangsu Polytechnic University | Kong Y.,Key Laboratory of Fine Petrochemicals of Jiangsu Province | Zhao W.,Jiangsu Polytechnic University | Yao S.,ChemChina Petroleum Development Corporation | And 4 more authors.
Journal of Applied Polymer Science | Year: 2010

Herein we report the electrosynthesis of polypyrrole with L-tryptophan (L-Trp) as a template to prepare molecularly imprinted polymers (MIPs). Over-oxidized polypyrrole films with cavities complementary to the template were used for the enantioselective detection of L-Trp and D-tryptophan (D-Trp). Important parameters, such as the electropolymerization potential, overoxidization potential and time, thickness of the poly-pyrrole films, and scanning rate of the stripping voltam- metric experiments, were varied to achieve an optimum sensor response. We found that L-Trp was inserted about 2 times higher into the imprinted polymer film than D-Trp. Also, in this study, an electrochemical quartz crystal microbalance technique was used to investigate the performance of overoxidized polypyrrole films. The enantio-selectivity of the MIPs was attributed to the cavities in the imprinted films, which were complementary to the target molecules, both in shape and in positioning of the functional groups. The results also suggest the feasibility of preparing MIPs by electropolymerization for the enan- tioselective recognition of other amino acid enantiomers. © 2009 Wiley Periodicals, Inc.

Kong Y.,Changzhou University | Kong Y.,Key Laboratory of Fine Petrochemicals of Jiangsu Province | Xu Y.,Changzhou University | Mao H.,Changzhou University | And 4 more authors.
Journal of Electroanalytical Chemistry | Year: 2012

An expanded graphite electrode (EGE) modified with intercalated montmorillonite (MMT) was developed for the electrochemical determination of catechol. Compared to the bare EGE and the EGE modified with natural MMT, the peak current of catechol on the cyclic voltammograms was significantly improved on the EGE modified with intercalated MMT. The remarkably increased specific surface area of MMT after intercalation plays a decisive role in the electro-catalytic oxidation of catechol. Various important factors such as the type of electrolyte and the content of intercalated MMT which influence the response of catechol on the modified EGE were also investigated in this paper. The amperometric sensor shows a linear response range between 10 and 1000 μM catechol with a correlation coefficient of 0.9987. The detection limit was calculated as 1.13 μM (S/N = 3). © 2012 Elsevier B.V. All rights reserved.

Kong Y.,Changzhou University | Kong Y.,Key Laboratory of Fine Petrochemicals of Jiangsu Province | Ma M.,Changzhou University | Mao H.,Changzhou University | And 2 more authors.
Analytical Methods | Year: 2012

A simple and reliable amperometric sensor for hydroquinone (HQ) determination is developed based on an intercalated montmorillonite (MMT) modified carbon paste electrode (CPE). The modified CPE significantly enhances the peak current of HQ on cyclic voltammograms and differential pulse voltammograms. The electro-catalytic properties of the intercalated MMT can be attributed to the remarkably increased specific surface area of MMT after the intercalation process, which leads to a higher accumulation efficiency for HQ at this modified CPE. The modified CPE shows a linear range between 5 and 2000 μM HQ with a correlation coefficient of 0.9997, and the detection limit is as low as 0.57 μM (S/N = 3). © 2012 The Royal Society of Chemistry.

Zhou Y.,Changzhou University | Ren X.,Changzhou University | Sheng C.,Changzhou University | Chen X.,Changzhou University | And 5 more authors.
Journal of Solid State Electrochemistry | Year: 2012

Selective determination of hydroquinone (HQ) in the presence of catechol (CC) was developed at an overoxidized poly(hydroquinone) (PHQ) electrode. The electrochemical polymerization of HQ was carried out by potentiostatic method on a glassy carbon electrode. The resulting PHQ was over-oxidized in 0.10 mol/L NaOH solution and thus poly (p-benzoquinone) was obtained. Two dihydroxybenzene isomers, HQ and CC, show different voltammetric behavior at the over-oxidized PHQ electrode. The peak current of HQ is much larger than that of CC with the same concentration, which is attributed to the different position of the hydroxyl groups in benzene ring of the two isomers. The results from electrochemical impedance spectroscopy also demonstrates that the overoxidized PHQ electrode has a stronger affinity for HQ over CC. © Springer-Verlag 2012.

Zhou Y.,Changzhou University | Luo S.,Changzhou University | Kong Y.,Changzhou University | Kong Y.,Key Laboratory of Fine Petrochemicals of Jiangsu Province
Chinese Journal of Chromatography (Se Pu) | Year: 2012

An effective method was developed for the determination of cholesterol in drainage oil by solid phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS). Firstly, the samples were purified by SPE on a column packed with silica. An extraction yield of 97% was obtained when a 20 mL of ethyl ether/n-hexane mixture (0.6-99.4, v/v) was used for washing the SPE column, and 10 mL of the same solvent mixture (l5:85, v/v) for desorbing cholesterol from the SPE column. Then the final extract was determined by GC-MS with electron impact ion source. The cholesterol was characterized according to retention time and characteristic fragments (m/z 213, 275, 301, 368, 386), and was quantitatively determined by external standard method in selected ion monitoring mode. The fragment of m/z 386 was selected as the target ion, and m/z 213 and m/z 275 were used as the reference ions. The average recovery was from 91.7% to 101%, and the relative standard deviations (RSDs) were below 6%, and the detection limit was 0.01 mg/L. A good linearity was obtained in the cholesterol concentration range of 0.24-6.0 mg/L with the correlation coefficient of 0.9996. The proposed method can be used to determine the cholesterol content in oil accurately, and the detection result can be one of the criteria judging the existence of drainage oil in edible oil. © 2010 Editorial Office of Chinese Journal of Chromatography, Dalian Institute of Chemical Physics, CAS.

Kong Y.,Changzhou University | Kong Y.,Key Laboratory of Fine Petrochemicals of Jiangsu Province | Li X.,Changzhou University | Yao C.,Changzhou University | And 2 more authors.
Journal of Applied Polymer Science | Year: 2012

A polypyrrole (PPy)-flake graphite composite was synthesized by in situ polymerization of pyrrole on flake graphite surface, and the resulting organic-inorganic composite material was developed as the conductive stationary phase in an electrode column for enantioselective recognition of tryptophan (Trp) enantiomers. Compared with the stationary phase made up with conducting PPy, the conductivity of the composite stationary phase was enhanced significantly. As a result, satisfactory enantioselectivity of Trp enantiomers can be achieved easily by modulating the potential applied on the electrode column. Various important parameters influencing the performance of the composite electrode column were investigated to obtain the optimum recognition efficiency. A recognition efficiency of 3.7 could be achieved under the optimum conditions. Enantioselectivity of the composite material for Trp enantiomers is attributed to the reversible doping/de-doping properties of PPy. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 Copyright © 2012 Wiley Periodicals, Inc.

Wang Y.,Changzhou University | Wang Y.,Key Laboratory of Fine Petrochemicals of Jiangsu Province | Zhou Y.,Changzhou University | Wang W.,Changzhou University | And 2 more authors.
Journal of the Electrochemical Society | Year: 2013

Sustained silver (Ag) electroless deposition onto copper (Cu) surface was achieved from a simple and stable solution, which only containing silver salt, choline chloride (ChCl) and H2O, without using of catalyst and reductant. The mechanism of Ag deposition in ChCl-H2O solution was proven by ultra violet spectroscopy and cyclic voltammetry techniques. Through a study of the Ag coatings using atomic absorption spectroscopy, X-ray diffractometer and scanning electron microscope, we demonstrate that sustained deposition of Ag was achieved in ChCl-H2O solution with mole ratio higher than 1 ChCl : 5 H2O and the calculated activation energy of Ag deposition was 13.0 kJ·mol-1. © 2013 The Electrochemical Society.

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