The reduction of L-cystine in hydrochloric acid at mercury drop electrodes

被引：17

作者：

Ralph, TR

Hitchman, ML

Millington, JP

Walsh, FC

机构：

[1] Univ Southampton, Sch Engn Sci, Electochem Engn Grp, Southampton SO17 1BJ, Hants, England

[2] Univ Strathclyde, Dept Pure & Appl Chem, Glasgow G1 1XL, Lanark, Scotland

[3] Johnson Matthey Fuel Cells, Swindon SN5 8AT, Wilts, England

[4] Univ Manchester, Sch Chem Engn & Analyt Sci, Manchester M60 1QD, Lancs, England

来源：

JOURNAL OF ELECTROANALYTICAL CHEMISTRY | 2006年 / 587卷 / 01期

基金：

英国工程与自然科学研究理事会;

关键词：

amino acids; disulphide adsorption; cysteinate formation; L-cystine; L-cysteine; mercury electrodes; linear sweep voltarnmetry; cyclic voltammetry; polarography; HMDE; SMDE; DME;

D O I：

10.1016/j.jelechem.2005.10.005

中图分类号：

O65 [分析化学];

学科分类号：

070302 ; 081704 ;

摘要：

The reduction of L-cystine in 0.1 mol dm(-3) HCl at 298 K has been studied at mercury electrodes. Dropping mercury electrode (DME), static mercury drop electrode (SMDE) and hanging mercury drop electrode (HMDE) modes were used with normal, sampled d.c. and differential pulse polarographic detection. The charge transfer kinetics for the irreversible reduction Of L-cystine were complicated by reactant and product adsorption, by the formation of cysteinate complexes between mercury and the product thiol as well as by formation of Hg2Cl2. High Tafel slopes of -182 mV per decade were observed with a cathodic transfer coefficient of 0.32. The diffusion coefficient of L-cystine was found to be 5.3 x 10(-10) m(2) s(-1) in 0.1 mol dm(-3) HCl and 4.2 x 10(-10) m(2) s(-1) in 2.0 mol dm(-3) HCl at 298 K. The mechanism Of L-cystine reduction at mercury has been discussed and the effects of pH and reactant concentration have been quantified. (c) 2005 Elsevier B.V. All rights reserved.

引用

页码：31 / 41

页数：11

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