An assay for the determination of the amount of glucose oxidase immobilised in an enzyme electrode

This paper presents a simple assay for the estimation of the amount of gluc ose oxidase immobilised onto the surface of enzyme electrodes. The two flav in adenine dinucleotide (FAD) cofactors were stripped from immobilised gluc ose oxidase using an 8 M urea solution. The resultant concentration of FAD in the urea solution was quantified using either fluorescence or voltammetr y to determine the amount of glucose oxidase on the electrode surface. The assay is applied to a variety of different enzyme electrodes and is verifie d for a monolayer enzyme electrode using a quartz crystal microbalance.