A disposable Laccase-Tyrosinase based biosensor for amperometric detection of phenolic compounds in must and wine

An amperometric biosensor for the detection of polyphenols in wine has been developed immobilizing the two enzymes Tyrosinase and Laccase on graphite screen printed electrodes modified with ferrocene. Different immobilization procedures have been carried out, the sensor operational parameters have been optimized, determining the best conditions and the analytical method for the analysis of samples. The biosensor has been then tested with real samples, using wines and musts supplied by Astra, experimental winery, in Imola (Italy). The biosensor gave good results when employed for wine analysis, showing a good agreement with the spectrophotometric data obtained with the Folin-Ciocalteu test, the official method for polyphenols' analysis in wine. On the other hand, the measurements on musts and wines recently bottled, were seriously affected by the presence of an high level of free sulphur dioxide. SO(2) is the likely responsible for enzyme activity inhibition on the sensor. Further studies are currently proceeding to find out the most suitable conditions to obtain results not influenced by the presence of sulphur dioxide. (C) 2009 Elsevier B.V. All rights reserved.