DIRECT ELECTROCHEMICAL CHARACTERIZATION OF SUPEROXIDE ANION PRODUCTION AND ITS REACTIVITY TOWARD NITRIC-OXIDE IN SOLUTION

We report in this study, and for the first time the direct and simulta neous electrochemical measurements of both nitric oxide and superoxide anion evolution and reactivity in solution. For this purpose, we have combined the use of two electrodes: a previously developed NO-sensor for the amperometric determination of NO and a carbon microelectrode f or the amperometric detection of superoxide anion. The latter electrod e displayed a potential use for the selective detection of O-2(-) (gen erated by the xanthine/xanthine oxidase reaction) with an acceptable s electivity against uric acid. Our electrochemical experiments were val idated by the Cytochrome c method and by the use of a different proced ure for the generation of the superoxide anions. Our results show that the use of the NO sensor provides the selective detection of NO witho ut any interference of the superoxide enzymatic generator. (C) 1997 El sevier Science S.A.