Os. Kim et K. Kusuda, ELECTROCHEMICAL-BEHAVIOR OF ALPHA-TOCOPHEROL IN A THIN-FILM OF NUJOL,A MODEL OF ADIPOSE-TISSUE, Bioelectrochemistry and bioenergetics, 33(1), 1994, pp. 61-65
It has been shown that cyclic voltammetry (CV) on a paste electrode, m
ade of graphite powder and an electroinactive oily material containing
a redox active compound, in an aqueous electrolytic solution provided
a well-defined cyclic voltammogram of the compound. The electrochemic
al oxidation of alpha-tocopherol (I) in the Nujol component of a Nujol
carbon paste electrode (CPE) produced both dienone cation (III) and a
lpha-tocopherylquinone (V), which increased on repeated cyclic voltamm
ograms. One-electron oxidation of I took place during a positive sweep
in the potential region between 100 and 300 mV/SCE. Subsequent oxidat
ion to cation m took place in the more positive potential region. Thes
e results were obtained using a series of CVs with increasing positive
switching potentials (PSPs). CV curves of I at high concentrations in
Nujol indicated that (1) the ring-opening reaction of III to produce
V takes place in lower ratio than at low concentrations, and (2) the a
mount of I which is involved in the electrochemical reaction is invers
ely proportional to the concentration of I in the Nujol component of t
he CPE. The observed phenomena are discussed on the basis of the mobil
ity of counter-ions in Nujol.