GRAPHITE BASED BIENZYME SENSORS

Abstract

Robust peroxidase/oxidase sensors based on both chemically modified and unmodified graphite electrodes were prepared. The sensorsacted atelectrode potentials of -0.2 V to 0.2 V vs Ag/AgCl electrode. The Sensors werespecific to glucose, alcohols, choline chloride, L- and D-amino acids and oxalic acid. The sensitivities of sensors ranged from 0.3 - 12 uA/mM and the determination ranges of metabolites were 0.01 - 20 mM. The concentration range of cholesterine determined using a hydrogen peroxide sensor and soluble cholesterol oxidase was 0.01 - 0.26 mM with a sensitivity of 0.25 mA/mM whendetermination was carried out using the in biocatalytic pre-concentration regime. The pH optima andthe longterm stabilities of the sensors depended largely on the properties of the oxidase immobilized