Electrochemical Behavior of Tocopherols on Microelectrodes in Acetic Acid Medium

Abstract

The electrochemical oxidation of α-, γ- and δ-tocopherols, as well as α-tocopheryl acetate were investigated by voltammetry at platinum microelectrodes in glacial acetic acid. Particular attention has been devoted to the mechanism of the electrode process of α-tocopherol and α-tocopheryl acetate in solutions containing sodium perchlorate as the background electrolyte. The mechanism of α-tocopherol oxidation involves an initial loss of one electron and one proton to form an appropriate radical. The process exhibits adsorption phenomena on the Pt surface. The optimal conditions for the voltammetric determination of α-tocopherol and α-tocopheryl acetate have been studied. From the results obtained it is clear that differential pulse voltammetry and square-wave voltammetry are the most appropriate techniques for the analytical purposes. It was proved that mono- and polyunsaturated fatty acids could be present in the analyte without causing interference.