Anodic Oxidation of Trolox in Aqueous Solutions

Electrochemical oxidation of trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) was investigated on glassy carbon (GC) electrodes in buffered aqueous solutions in the pH range of 1.0-8.8. The results were interpreted in terms of the formation of phenoxyl radicals, and their subsequent dimerization (radical-radical coupling, i.e. DIM1). Dimerization rate constants were estimated from peak heights. pKa value of the carboxyl group was determined by potentiometric acid/base titration.