ELECTROCHEMICAL OXIDATION OF DIHYDRONICOTINAMIDE ADENINE-DINUCLEOTIDE(NADH) ON SINGLE-CRYSTAL GOLD ELECTRODES

The electro-oxidation of dihydronicotinamide adenine dinucleotide (NAD H) on three low-index basal single crystal gold faces was studied in a phosphate buffer solution. The reaction was found highly structure-se nsitive; the Au(100) and Au(111) faces showed a high electrocataiytic activity, while the Au(110) face was much less active. The high electr ocatalytic effect was attributed to the oxidation-mediator ability of the partially discharged OH(l-r-) species on the gold surface. The str uctural effect of the gold faces on the electro-oxidation of NADH may result from the difference in the adsorption of NAD(+), via its pyridi ne moiety as the adsorption site, on the different gold faces. The pos sibility of developing a highly sensitive NADH sensor based on the ele ctrochemical faceting technique is suggested.