ELECTRODE PROCESSES ON AN ENZYME EMBODIED ELECTRODE

An enzyme embodied electrode (EEE) is an electrochemical biosensing de vice fabricated by direct immobilization of enzyme on a platinized ele ctrode. In order to elucidate the reaction scheme of an EEE, the pulse voltammetric technique was employed, in which a potentiostatic pulse was applied after the preoxidation pulse and the following open circui t period, sequentially. A reaction scheme was proposed by taking subst rate and product diffusion in the micropores of platinum black into ac count, besides the enzymatic and electrochemical reactions. During the open circuit period the concentration profile of hydrogen peroxide wa s assumed to reach a steady state when the production of hydrogen pero xide equilibrated with the diffusion at the microporous electrode. Ass uming a steady state concentration profile at the balanced state, an a ppropriate solution was deduced for a differential equation that expre sses enzymatic production, electrochemical oxidation and diffusion of hydrogen peroxide to bulk solution. This expression explained well the observed transient current that decayed exponentially and the proport ionality to the glucose concentration.