An interference-free first generation alcohol biosensor based on a gold electrode modified by an overoxidised non-conducting polypyrrole film

An interference-free first generation alcohol biosensor based on alcohol oxidase immobilized, by glutaraldehyde co-crosslinking with bovine serum albumin, on a perm-selective electropolymerized film modified gold electrode is described. The use, in place of platinum, of a gold electrode, properly conditioned by an electrochemical pre-treatment, allowed the elimination of the electrode fouling and of the interference caused by the direct alcohol oxidation at the electrode surface. The efficiency of overoxidized polypyrrole and poly-ortho-phenylendiamine as anti-interferent perm-selective films towards the most common electroactive interferents was also investigated. The low response time and the fabrication procedure employed in this study allowed the use of the biosensor in a flow injection system equipped with a conventional thin-layer electrochemical cell. The biosensor showed a high sensitivity, a good stability and a complete Suppression of electroactive interferences in operational conditions. Biosensor performances were tested by the rapid determination of the alcohol content in just diluted wine samples and the results compared well with those obtained with the classical method of distillation. (c) 2006 Elsevier B.V. All rights reserved.