Application of biosensor with amperometric detection for determining ethanol

Abstract

Determination of ethanol content is one of the most important routinely performed tests in the field of wineries, breweries and liquor producers, and a sensor system has been developed for this purpose. The sensor was based on a thin-layer enzyme cell, in which alcohol oxidase (EC 1.1.3.13) was immobilized on a protein membrane. The product of the enzyme reaction was determined by an amperometric technique. In the amperometric cell, platinum–Ag–AgCl–platinum electrodes were used. Having found the optimum conditions of pH, temperature and flow rate, the statistical parameters of the analysis were established. The linear range of determination was between 1 and 8% v/v of ethanol, and the detection limit was 0.1% v/v. When injecting standard solutions, the error was 0.14% v/v. The lifetime of the thin-layer cell was more than 3 weeks and more than 250 samples were analysed during this period. The ethanol content of several samples was determined with this sensor, and the results were compared with those of a manual method. The correlation coefficient in the range 4–7% v/v of ethanol was found to be 0.992. The results showed that ethanol can be determined, at the required sensitivity, by means of this biosensor.