A new amperometric enzyme electrode for alcohol determination

A new enzyme electrode for the determination of alcohols was developed by immobilizing alcohol oxidase in polvinylferrocenium matrix coated on a Pt electrode surface. The amperometric response due to the electrooxidation of enzymatically generated H2O2 was measured at a constant potential of +0.70 V versus SCE. The effects of substrate, buffer and enzyme concentrations, pH and temperature on the response of the electrode were investigated. The optimum pH was found to be pH 8.0 at 30 degreesC. The steady-state current of this enzyme electrode was reproducible within +/-5.0% of the relative error. The sensitivity of the enzyme electrode decreased in the following order: methanol > ethanol > n-butanol > benzyl alcohol. The linear response was observed up to 3.7 mM for methanol, 3.0 mM for ethanol, 6.2 mM for n-butanol, and 5.2 mM for benzyl alcohol. The apparent Michaelis-Menten constant (K-Mapp) value and the activation energy, E-a, of this immobilized enzyme system were found to be 5.78 mM and 38.07 kJ/mol for methanol, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.