Article révisé par les pairs
Résumé : 2‐methoxycarbonyl‐1‐methyl‐3‐methylthio‐pyridinium iodide (Ia), 2‐carboxy‐1‐methyl‐3‐methylthio‐pyridinium iodide (Ib), 3‐mercapto‐2‐methoxycarbonyl‐1‐methyl‐pyridinium iodide (IIa) and 2‐carboxy‐3‐mercapto‐1‐methyl‐pyridinium iodide (IIb) have been studied by recent electrochemical techniques such as direct (DC), alternating current (AC), differential pulse polarography (DPP) and cyclic voltammetry. The influence of the pH has been observed and put in connection with the structure of the compounds studied. Cyclic voltammetry has permitted to differentiate Ia and Ib by the existence of reversible phenomena that become evident only for the carboxycompound. The study of the influence of the concentration has permitted to set up the best conditions for the determination of these compounds by direct current (DC) and differential pulse polarography (DPP). Copyright © 1982 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim