Voltammetric Study of Some Synthetic Antioxidants on Platinum Microelectrodes in Acetic Acid Medium

Abstract

Abstract The electrochemical oxidation of the antioxidants tert ‐butylhydroquinone (BHQ), tert ‐butyl‐4‐hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) has been investigated by voltammetry at platinum microelectrodes in glacial acetic acid containing sodium perchlorate or sodium acetate as a background electrolyte. BHQ, a compound with para‐diphenyl groups, was typically found to have lower oxidation potential than isolated phenols BHA and BHT. Particular attention has been devoted to the mechanism of the electrode processes. Linear scan voltammograms recorded under steady‐state conditions showed well‐defined oxidation waves of the compounds studied even at relatively high concentrations (2 mM), due to a low proclivity for adsorption of the oxidation products on the electrode surface in acetic acid. The optimal conditions for the voltammetric determination of BHQ, BHA and BHT have also been studied. The results reveal that sensitive response for all the oxidants studied can be obtained in solution containing 0.1 M NaClO 4 and 0.1 M CH 3 COONa by using the differential pulse voltammetry and square‐wave voltammetry. Peak currents were found to vary linearly with the antioxidant concentration over the range 3×10 −5 −1×10 −3 M.