AMPEROMETRIC BIOSENSOR FOR ETHANOL BASED ON IMMOBILIZATION OF ALCOHOL-DEHYDROGENASE ON A NICKEL HEXACYANOFERRATE MODIFIED MICROBAND GOLD ELECTRODE

Alcohol dehydrogenase (ADH) has been immobilized on a nickel hexacyano ferrate modified microband gold electrode surface by a glutaraldehyde/ bovine serum albumin (BSA) cross-linking procedure to provide a new am perometric sensor for the assay of ethanol. The resulting enzyme elect rode exhibits excellent electrocatalysis for the oxidation of reduced nicotinamide-adenine dinucleotide (NADH). The amperometric determinati on is based on the electrochemical detection of NADH which is generate d in the enzymatic reaction of ethanol with NAD(+) under catalysis of ADH. The influence of various experimental conditions was examined for the determination of the optimum analytical performance. The sensor r esponds rapidly to ethanol with a detection limit of (5.0 +/- 0.3) x 1 0(-7) mol l(-1). The response current increases linearly with ethanol concentration up to 5 mmol l(-1). The sensor remains relatively stable for about 1 week. (C) 1997 Published by Elsevier Science B.V.