ELECTROCHEMICAL CHARACTERIZATION OF ELECTROPOLYMERIZED FILM OF NAPHTHOL-GREEN-B AND ITS ELECTROCATALYTIC ACTIVITY TOWARD NADH OXIDATION

A stable electroactive thin film of poly(naphthol green B) (PNGB) was deposited on the surface of a glassy carbon electrode by cyclic voltam metry from an aqueous solution containing naphthol green B (NGB). Cycl ic voltammograms of PNGB indicated the presence of a couple of well-de fined redox peaks with the formal potential of -50 mV (20 mV s(-1)). T he formal potential shifts linearly in the negative direction with inc reasing solution pH, with a slope of -56.3 mV per pH unit. The PNGB-mo dified glassy carbon electrode shows excellent electrocatalytic activi ty toward NADH oxidation in Britton-Robinson buffer solution (pH 7.0) with an overpotential ca. 480 mV lower than that of the bare electrode . The catalytic rate constant of the modified glassy carbon electrode for the oxidation of NADH is determined by rotating-disk electrode mea surements. (C) 1998 Academic Press.