IMMOBILIZATION OF GLUCOSE-OXIDASE IN A POLY [VINYL ALCOHOL] MATRIX ON PLATINIZED GRAPHITE-ELECTRODES BY GAMMA-IRRADIATION

The strategy of immobilizing a biomolecule of analytical interest in a polymer matrix on an electrode surface by crosslinking with gamma radiation, was examined using the enzyme glucose oxidase (GO) and the polymer poly[vinyl alcohol] (PVAL), with and without the polyfunctional monomer, allyl methacrylate (AM). GO immobilized on platinized graphite surfaces enables glucose to be detected by oxidation of enzyme-generated H2O2 at 300 mV vs Ag/AgCl. The GO/polymer modified electrode exhibits fast response (20 to 60 s), linearity range between 50 μM and 3 mM, good sensitivity (1·39 μA/mm) and a detection limit of 50 μM. On non-platinized electrodes, the sensitivity is greater (1·53 μA/mm), but a higher applied potential (1 200 mV) is required. Optimum response is obtained with a radiation dose of 3-5 Mrad. Repeated use of electrodes for over 60 days showed no significant change in these characteristics. © 1989.