?Highly sensitive and selective amperometric glucose biosensors based on metallized electrodes and polymeric matrices"

G. A. RIVAS, M. D. RUBIANES, M. C. RODRIGUEZ, S. A. MISCORIA AND G. D. BARRERA.

San Pedro, Brasil

Otro; 54th ISE Meeting; 2003

International Society of Electrochemistry

This communication reports on the advantages for the highly sensitive and selective amperometric glucose biosensing. Two approaches have been used for the design of these biosensors. ln one case glassy carbon and screen printed electrodes were modified by the electrodeposition of rhodium onto the surface of the electrode followed by the adsorption of glucose oxidase and the final electropolymerization of tyramine The response of the biosensor was evaluated from the amperometric signal at 0.700 V in connection with the oxidation of hydrogen peroxide Under the optimum conditions the response to glucose was highly selective, even for large excess of uric acid and ascorbic acid. In the other case a composite carbon electrode was modified by dispesion of platinum or palladium microparticles and glucose oxidase in a graphite paste covered by a melanin-type polymer electrogenerated from catecholamines The polymer obtained by electropolymerization of L-dopa demonstrated to be the most effective as perm-selective layer, largely decreasing the interference of easily oxidizable compounds such as ascorbic acid and uric acid The resulting electrode also presents the advantage to improve the linear dynamic range for glucose (up to 30 mM). Therefore, the combination of the excellent catalytic properties of rhodium, platinum and palladiom towards hydrogen peroxide oxidation, the biocatalytic properties of glucose oxidase towards glucose and the pem-selective properties of a melanin-type polymer has allowed us to obtain highly sensitive and selective glucose biosensors".