The reduction of l-cystine hydrochloride at stationary and rotating disc mercury electrodes


Ralph, T.R., Hitchman, M.L., Millington, J.P. and Walsh, F.C. (2005) The reduction of l-cystine hydrochloride at stationary and rotating disc mercury electrodes. Electrochimica Acta, 51, (1), 133-145. (doi:10.1016/j.electacta.2005.04.012).

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Description/Abstract

The kinetics of l-cystine hydrochloride reduction have been studied at a mercury-plated copper rotating disc electrode (RDE) and at a stationary mercury disc electrode (SMDE) in 0.1 mol dm−3 HCl at 298 K. The reduction of the disulphide is irreversible and hydrogen evolution is the major side reaction. In contrast to steady state electrode kinetic studies at a mercury drop electrode (which shows a well-defined limiting current), the mercury-plated Cu RDE shows overlap between disulphide reduction and hydrogen evolution. These effects are attributable to strong reactant adsorption with a calculated surface coverage close to 100%. A Tafel slope of −185 mV per decade is found with a cathodic transfer coefficient of 0.32 and a formal rate constant of 6.7 × 10−9 m s−1. The relative merits of steady state voltammetry at a mercury-plated copper RDE and linear sweep voltammetry at the SMDE are discussed, as is the mechanism of l-cysteine hydrochloride formation.

Item Type: Article
ISSNs: 0013-4686 (print)
Related URLs:
Keywords: l-cysteine hydrochloride, l-cystine hydrochloride, mercury-plated copper, rotating disc, stationary mercury drop
Subjects: T Technology > TP Chemical technology
Q Science > QD Chemistry
Q Science > QC Physics
Divisions: University Structure - Pre August 2011 > School of Engineering Sciences
ePrint ID: 23753
Date Deposited: 21 Mar 2006
Last Modified: 27 Mar 2014 18:12
Contact Email Address: f.c.walsh@soton.ac.uk
URI: http://eprints.soton.ac.uk/id/eprint/23753

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