Catalytic Oxidation of Reduced Nicotinamide Adenine Dinucleotide by Graphite Electrodes Modified with Adsorbed Aromatics Containing Catechol Functionalities

Article abstract of DOI:10.1021/ac00236a007

4-<2-(2-naphthyl)vinyl>catechol (NSCH2) and 4-<2-(9,10-ethanoanthracen-9-yl)vinyl>catechol (ASCH2) were adsorbed on graphite electrodes.The naphthalene and the ethaneanthracene ring systems were used as anchors to the graphite.The catechol group is free to move out into the electrolyte solution.The electron transfer between the 1,2-hydroquinone functionality and the graphite was fast.The surface coverage was at most 9 x 10^-9 mol cm ^-2.The coenzyme reduced nicotinamide adenine dinucleotide (NADH) could be catalytically oxidized by the immobilized mediating groups.The overvoltage of the NADH oxiadation decreased from 410 mv vs.SCE at the unmodified graphite electrode to 185 mV at the NSCH2 covered electrode at pH 7.=.The reaction rate of the ASCH2 covered electrode was lower than that of the NSCH2 electrode.After 30 min of continuous electrochemical cycling of pH 7.0, 30percent of the original coverage remained for the NSCH2 electrode.