BIOMOLECULAR SENSORS FOR NEUROTRANSMITTER DETERMINATION - ELECTROCHEMICAL IMMOBILIZATION OF GLUTAMATE OXIDASE AT MICROELECTRODES IN A POLY(O-PHENYLENEDIAMINE) FILM

The adsorption of glutamate oxidase onto 25 mum and 10 mum platinum microelectrodes followed by immobilization in an electrochemically polymerized non-conducting polymer, poly(o-phenylenediamine), is described as a method of fabricating an enzyme electrode for the amperometric determination of glutamate. The response of the enzyme electrodes were found to be highly reproducible with a linear dynamic range up to approximately 15 mmol dm-3. The response of the 25 mum and 10 mum enzyme electrodes to glutamate were analysed using an established kinetic model and the potential application of the sensor for the study of neurotransmitter dynamics was investigated. The sensor was stable over a period of 30 days and the polymeric film was found to reduce interference from the electroactive compounds, uric acid and ascorbic acid.