Improvement of the output characteristics of amperometric enzyme electrode by using the powder microelectrode technique

Application of the powder microelectrode technique to the fabrication of enzyme electrodes can result in significant improvement of the output behaviours of an amperometric enzyme electrode. The theoretical kinetic equation of the powder enzyme electrode is derived and compared with that of the planar enzyme electrode, together with a simple method for the estimation of apparent Michaelis constant K-m' from the response of the powder enzyme electrode. The glucose oxidase (GOD) electrode is used as the model to verify the theoretical equations. Values of K-m' estimated from experimental data obtained with powder electrodes are closer to the intrinsic values of the same enzyme system in bulk phase. The working life of the enzyme electrode was found to improve and the interfering effects of various bioactive molecules were found to be less in the case of powder enzyme electrodes. (C) 1998 Published by Elsevier Science Limited.