Determination of the activity of immobilized glucose oxidase with thin-layer electrochemical techniques

In this study, thin-layer electrochemistry is studied as a method of determining the activity of glucose oxidase (GOx) covalently immobilized onto thin poly(etherurethaneurea) films. Thin layer electrochemical cells confine the entire quantity of reactant solution within a thin-layer (10^-3 to 10^-2 cm) at the working electrode surface. Thin-layer cells are simple and inexpensive to fabricate and the electronic control circuits necessary for thin-layer electrochemistry are readily available. The attractive features of thin-layer electrochemical techniques include high sensitivity in very small volumes, the ability to study highly irreversible reactions, relatively simple descriptive equations for quantitative studies, and rapid exhaustive electrolysis. The technique employed was cyclic voltammetry, in which the current is measured as a function of a linearly varying applied potential at a working electrode. An attractive feature of cyclic voltammetry is its ability to probe the fate of a redox species over multiple sweeps.