Mechanism of Electrochemical Interaction between Sulfur-Containing Amino Acids and Anodically Polarized Platinum Electrode

Electrooxidation of cysteine and methionine on a platinum electrode in solutions with various pH values is studied by the RDE and linear-sweep voltammetry methods. Based on this study and previous adsorption measurements, kinetic equations and mechanisms of main processes, which occur on the anodically polarized platinum electrode in the presence of the amino acids and lead to electrocatalytic dissolution of platinum, are proposed. Anodic dissolution of platinum in the presence of cysteine and methionine is accelerated due to immediate involvement of the sulfur atom in the adsorption and electrooxidation on the platinum electrode surface.