IMMOBILIZATION OF GLUCOSE-OXIDASE ON A CARBON SURFACE DERIVATIZED BY ELECTROCHEMICAL REDUCTION OF DIAZONIUM SALTS

Glassy carbon disk electrodes grafted with superficial 4-phenylacetic groups through electrochemical reduction of the corresponding diazonium salt were used for glucose oxidase covalent immobilization. Protein attachment was confirmed by means of X-ray photoelectron spectroscopy and the activity of the enzyme modified electrode was ascertained by performing enzymatic electrocatalysis. The present method does not cause any roughening of the electrode surface and concomitant increase of a background current thus allowing precise measurements using transient electrochemical techniques such as cyclic voltammetry. As diazonium salts (which upon reaction provide the anchoring site) can be synthesized with various substituents, it is conceivable that customized attachment of enzymes and biochemical reagents could be designed.