Redox electrode for monitoring oxidase-catalyzed reactions

Abstract

A new approach to the measurement of hydrogen peroxide is described in this report. Redox potentiomet~c electrodes have been used to monitor dehydrogenasecatalyzed reactions [1,2]. By including diaphorase and a redox couple (ferricyanide and ferrocyanide ions) in the reaction medium, the production of NADH becomes detectable with a redox electrode [l]. In the presence of diaphorase NADH reduces ferricyanide ion to ferrocyanide ion. The change in the ferroand ferricyanide concentration ratio alters the redox potential. A similar approach can be adapted for the measurement of hydrogen peroxide in the oxidase-catalyzed reactions. Hydrogen peroxide oxidizes ferrocyanide ion to ferricyanide ion with peroxidase as a catalyst.