ROBUST GRAPHITE-BASED BIENZYME SENSORS

Mediatorless peroxidase/oxidase sensors based on graphite electrodes have been prepared. The sensors act at electrode potentials of 0.0-0.2 V versus an Ag/AgCl electrode and are specific to glucose, methanol, choline, L-amino acids and oxalic acid; the sensitivities range from 0.3-12-mu-A/mM and the determination ranges of metabolites are 0.01-20 mM. The pH optima and long-term stabilities are dependent on the properties of immobilized oxidases.