SOL-GEL DERIVED CERAMIC-CARBON ENZYME ELECTRODES - GLUCOSE-OXIDASE ASA TEST-CASE

Several types of amperometric biosensors comprised of immobilized gluc ose oxidase in chemically-modified ceramic-carbon matrices are compare d. The electrodes are comprised of several building blocks each perfor ming a specific function. Glucose oxidase is used to catalyze the bio- oxidation of glucose; carbon powder imparts conductivity and favorable electrochemical characteristics; the Ormosil network provides rigidit y and porosity; and the organic modification of the Ormosil imparts co ntrolled surface polarity. Additionally, hydrophilic chemical modifier s are incorporated in order to control the size of the wetted, electro active layer; high dispersion of inert metal catalysts is used to enha nce hydrogen peroxide oxidation and redox mediators may be co-immobili zed when oxygen independent response is desirable. The electrodes can be prepared either in the form of thick supported film, useful for dis posable electrodes or as bulk-modified, disk shape electrodes, which c an be used as renewable surface electrodes.