A study of the kinetics of the reaction between ferrocene monocarboxylic acid and glucose oxidase using the rotating-disc electrode

Abstract

In this paper we present the result of a study of the glucose|glucose oxidase|ferrocene monocarboxylic acid system using the rotating-disc electrode. The results of experiments carried out over a wide range of experimental conditions (rotation speed, enzyme, mediator and substrate concentration) are compared with the theoretical model presented by Albery et al. ( J. Electroanal. Chem., 323 (1992) 77). Good agreement between the experiments and theory is demonstrated for most of the available range of experimental conditions, and the method is shown to be a good one for the determination of the rate of reaction of the enzyme and mediator. In the case where the enzyme substrate kinetics are rate limiting it is shown that the correct interpretation of the data is more difficult because of the effects of concentration polarization of the substrate. An approach to overcoming this problem is described. The experimental techniques and analysis described in this paper should be generally applicable to studies of the homogeneous kinetics of mediated enzyme reactions.