Electrochemical properties of α-tocopherol in aqueous electrolytes after its previous extraction into the glassy carbon paste from aqueous-acetonic mixture

Abstract

Study on electrochemical behavior of lipophilic α-tocopherol, which is recognized as the most active form of vitamin E, was performed using extraction voltammetry in solely aqueous supporting electrolytes. In the first step, α-tocopherol was extracted into the silicone oil, acting as a binder of glassy carbon paste electrode, from aqueous-organic mixture. Generally, the extraction into the electrode material was carried out from solution containing 50 µmol dm−3 α-tocopherol and 60 % acetone for period of 240 s and corresponding stirring rate of 400 rpm. Electrochemical study was undertaken subsequently by cyclic voltammetry after placing the electrode in aqueous supporting electrolyte. Due to the accumulation effect of extraction, voltammetric records exhibited intensive current signals in acidic media when compared to those obtained at solid glassy carbon electrode. Investigations revealed a promising application of carbon paste electrodes for sensitive analysis of α-tocopherol or other electroactive lipophilic species after their extractive preconcentration.