HIGH-CURRENT DENSITY WIRED QUINOPROTEIN GLUCOSE-DEHYDROGENASE ELECTRODE

Glucose electrodes were prepared by ''wiring'' quinoprotein glucose dehydrogenase, GDH (EC 1. 1.99. 17) to glassy carbon with an osmlum complex containing redox-conducting epoxy network. Their current density at 70 mM glucose concentration reached 1.8 mA cm-2 when 15 mug cm-2 of the enzyme having an activity of 250 units mg-1 was applied to the electrode. Under the same conditions, electrodes made with glucose oxidase (GOX) of similar activity (250 units mg-1) had a maximum current density of 0.66 mA cm-2. The maximum current density was reached with 8% GDH in the redox film. The current density was almost flat through the 6.3-8.8 pH range and was not altered when the solution was either aerated or argon purged. It decreased st 25-degrees-C to half its initial value in 8 h.