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 outp ut behaviours of an amperometric enzyme electrode. The theoretical kin etic equation of the powder enzyme electrode is derived and compared w ith that of the planar enzyme electrode, together with a simple method for the estimation of apparent Michaelis constant K-m' from the respo nse of the powder enzyme electrode. The glucose oxidase (GOD) electrod e 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 p hase. The working life of the enzyme electrode was found to improve an d the interfering effects of various bioactive molecules were found to be less in the case of powder enzyme electrodes. (C) 1998 Published b y Elsevier Science Limited.