University of North Florida
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Contact Info

Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Xiao Yuan Li

Abbrev:
Li, X.Y.
Other Names:
Xiao-yuan Li, Xiaoyuan Li
Address:
Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
Phone:
NA
Fax:
NA

Citations 4

"Electrochemical Study And Flow Injection Amperometric Detection Of Trace NO2 At CuPtCl6 Chemically Modified Electrode"
Talanta 2000 Volume 51, Issue 6 Pages 1107-1115
Jianhong Pei and Xiao-yuan Li

Abstract: A thin film of mixed-valent CuPtCl6 is deposited on a glassy carbon electrode by continuous cyclic scanning in a solution containing 3 x 10^-3 M CuCl2 + 3 x 10^-3 M K2PtCl6 + 1 M KCl in the potential range from 700 to -800 mV. The cyclic voltammetry is used to study the electrochemical behaviors of nitrite on CuPtCl6/GC modified electrode and the electrode displays a good catalytic activity toward the oxidation of nitrite. The effects of the film thickness, pH, the electrode stability and precision have been evaluated. Experiments in flow injection analysis are performed to characterize the electrode as an amperometric sensor for the detection of nitrite. The modified electrode shows a wide dynamic range, quite a low detection limit and short response time. The linear relationship between the flow injection peak currents and the concentrations of nitrite is at a range of 1 x 10^-7-2 x 10^-3 M with a detection limit of 5 x 10^-8 M.

"Determination Of Underivatized Amino Acids By High-performance Liquid Chromatography And Electrochemical Detection At An Amino Acid Oxidase Immobilized CuPtCl6 Modified Electrode"
Fresenius J. Anal. Chem. 2000 Volume 367, Issue 8 Pages 707-713
Jianhong Pei, Xiao-yuan Li

Abstract: AII amperometric sensor for amino acids based on the immobilization of amino acid oxidase on the surface of a CuPtCl6/GC is described. The amperometric current is due to the oxidation of H2O2 liberated during the enzyme reaction on the surface of the enzyme electrode. The electrode response characteristics as well as kinetic parameters have been evaluated. The enzyme electrode was characterized as an electrochemical biosensor, which was used as detector in high performance liquid chromatography (HPLC) for the determination of a mixture of amino acids with satisfactory results.

"Electrocatalysis And Flow Injection Analysis Of Hydrogen And Organic Peroxides At CuPtCl6 Chemically Modified Electrodes"
Electroanalysis 1999 Volume 11, Issue 16 Pages 1211-1217
Jianhong Pei, Xiao-yuan Li

Abstract: Cyclic voltammetry was used to investigate the electrochemical behavior of peroxides, both hydrogen and organic, on the CuPtCl6/GC modified electrode which displayed great electrocatalytic activity in the redox of peroxide. The results show that the electrochemical processes of peroxide on the CuPtCl6/GC modified electrode are controlled by the diffusion of the species, and the reduction of dissolved oxygen overlaps with the reduction of H2O2, but has no influence on the oxidation of H2O2 The modified electrode was characterized as an electrochemical sensor for the detection of peroxide, both hydrogen and organic, ina flow injection system. The electrode exhibited a number of great advantages such as a very wide dynamic range, quite low detection limits, high stability and short response times and simple preparation. The linear relationship between the flow injection peak currents and the concentrations of H2O2 is in a range of 5 x 10^-8 to 5 x 10^-3 M With a detection limit of 1 x 10^-8 M. The linear response to tert-butyl hydroperoxide (TBHP) is in a range of 1 x 10(5) to 2 x 10^-3 M with a detection limit of 5 x 10^-6 M.

"Xanthine And Hypoxanthine Sensors Based On Xanthine Oxidase Immobilized On A CuPtCl6 Chemically Modified Electrode And Liquid Chromatography Electrochemical Detection"
Anal. Chim. Acta 2000 Volume 414, Issue 1-2 Pages 205-213
Jianhong Pei and Xiao-yuan Li

Abstract: Xanthine oxidase has been immobilized on the surface of a CuPtCl6/glassy carbon chemically modified electrode. The enzyme electrode displays a quick and sensitive response to xanthine and hypoxanthine. The observed steady-state current is due to the oxidation of hydrogen peroxide Liberated during the enzyme reaction on the surface of the enzyme electrode. The effects of enzyme loading, pH, temperature, and applied potential have been discussed. The enzyme electrode was characterized as an amperometric sensor for xanthine (6 x 10^-7-2 x 10^-4 M) and hypoxanthine (5 x 10^-7-2 x 10^-4 M) with the detection limit of 1 x 10^-7 M. Liquid chromatographic separation coupled with the enzyme electrode as an electrochemical detector was used to analyze the mixtures of xanthine and hypoxanthine.
Xanthine Hypoxanthine Electrode Electrode Potentiometry HPLC Detector Optimization