Determination of Reactive Intermediates During Anodic Oxygen-transfer Reactions at Lead Dioxide

The anodic discharge of water to produce adsorbed hydroxyl free radicals（·OH） is considered to be a prerequisite to anodic O-transfer reactions at a PbO2 electrode. In this work,a method was studied by means of high-performance liquid chromatography（HPLC） combined with electrochemical detection（ED） so as to investigate the production of hydroxyl free radicals（·OH） in the process of the anodic discharge of H2O at a PbO2 electrode. The voltammetric data obtained at the PbO2 electrode for the oxidation of salicylic acid to salicylate hydroxylation products（DHBAs） and the detection of DHBAs by means of HPLC-ED confirm the proposed mechanism.