The electrogeneration of hydroxyl radicals was studied at a synthetic B-doped diamond (BDD) thin film electrode. Spin trapping was used for detection of hydroxyl radicals with 5,5-dimethyl-1-pyrroline-N-oxide and with salicylic acid using ESR and liq. chromatog. measurements, resp. The prodn. of H2O2 and competitive oxidn. of formic and oxalic acids were also studied using bulk electrolysis. Oxidn. of salicylic acid gives hydroxylated products (2,3- and 2,5-dihydroxybenzoic acids). The oxidn. process on BDD electrodes involves hydroxyl radicals as electrogenerated intermediates. [on SciFinder (R)]