Sensing of Hydrogen Peroxide by a Peroxidase-mediator Co-immobilized Electrode

Abstract

Films in which peroxidase and several kinds of water insoluble mediators were co-immobilized were produced using cross-linked poly (vinyl alcohol). These films were attached to glassy carbon electrodes and the characterisitics of these electrodes as the hydrogen peroxide sensor were investigated.
When 1, 4-naphthoquinone and 2-methyl-1, 4-naphthoquinone were used as media tors, cathodic current increased and anodic current decreased in the cyclic voltammogram by the addition of hydrogen peroxide because of the cyclic reaction of electroreduction and enzyme oxidation. On the other hand in the case of ferrocene used as a mediator, not only cathodic current but also anodic current increased in the cyclic voltammogram since hydrogen peroxide was consumed by a reaction with ferrocene and peroxidase before hydrogen peroxide diffuses in the vicinity of the surface of the glassy carbon electrode.