Estimation of the antioxidative properties of tocopherols - an electrochemical approach

The electrochemical behaviour of tocopherols on solid platinum electrodes, using cyclic voltammetry, linear sweep voltammetry and differential pulse v oltammetry in non-aqueous media, was studied. D-x-, D-gamma-, and D-delta-t ocopherol (E vitamins) provided well-defined voltammograms, each of them ex hibiting a characteristic peak (respectively 0.550 V, 0.700 V and 0.750 V v s. a silver, silver chloride/chloride reference electrode). The differentia l pulse voltammograms were suitable for the electroanaytical determination, in the respective concentration ranges of (2 x 10(-8) divided by 1 x 10(-5 )) mol 1(-1), (2.2 x 10(-8) divided by 1.4 x 10(-6)) mol 1(-1) and (2.2 x 1 0(-8) divided by 3.31x10(-5)) mol 1(-1), of alpha-, gamma-, delta- tocopher ol. An electrochemical estimation of the tocopherols' antioxidative propert ies, related to the free radical 2,2'diphenyl-1-pycrilhydrazil was made. Th e maximum value of the characteristic peak of tocopherol decreased with DPP H concentration.