Ethanol Determination in Wine with an Immobilized Enzyme Electrode

The purpose of this work was to demonstrate the accuracy and precision of a new method for ethanol determination. This method utilizes a thin microporous membrane containing immobilized alcohol oxidase (E.C. 1.1.3.13) which is mounted on an amperometric electrode. When ethanol enters the membrane it is rapidly oxidized producing hydrogen peroxide and acetaldehyde. The hydrogen peroxide is oxidized at the electrode giving rise to a signal current directly proportional to hydrogen peroxide concentration, and hence to ethanol concentration. The coefficient of variation for six analyses of eight wine samples was better than 1.0%, and agreement with A.O.A.C. specific gravity method was excellent.