DEVELOPMENT OF HIGH SENSITIVE AMPEROMETRIC ENZYME ELECTRODES

Abstract

High sensitive amperometric enzyme electrodes based on chemical emplification in biocatalytic membranes or biocatalytic accumulation of oxidation-reduction equivalents on chemically modified electrodes have been designed. Chemical amplification via cyclic substrate conversion in biocatalytic membranes proceeds merely at high diffusion moduli values. The amplification degree depends on the catalytic activity of membranes and their thickness as well. The response of the electrodes with cyclic substrate conversion is slow. High sensitive determination of aromatic amines was carried out with the use of enzyme electrodes in the biocatalytic layer of which the substrate-substrate activation of peroxidase catalysis occurs. The activation in the bienzyme glucose oxidase/peroxidase system is observed at high glucose concentrations. Biocatalytic product accumulation, accomplished through the apoenzyme and cofactor interaction, enables to determine a substance in concentration relative to the dissociation constant of choloenzyme. The accumulation of oxidation-reduction equivalents on chemically modified electrodes with their subsequent electrochemical conversion makes the basis for stripping analysis, ascertaining the determination of low metabolite concentrations.