Abstract

The potentiometric response resulting from the sequential addition of reduced thiols to a benzoquinone/hydroquinone couple has been investigated. The system has been shown to offer a simple route through which thiol could be quantified but a discrepancy in the reaction stoichiometry between glutathione and cysteine was observed. A mechanistic appraisal of the quinone-thiol interactions has been conducted and the proposed reaction pathways corroborated by spectroscopic analysis. (C) 2003 Published by Elsevier B.V.