Two New Different Enzyme Devices for Ethanol Determination in Alcoholic Beverages. Comparison, Correlation and Statistical Data.

New different enzyme amperometric devices for the determination of ethanol in alcoholic beverages were developed by immobilizing alcohol oxidase or catalase in k-Carrageenan gel layer overlapping an amperometric gaseous diffusion Clark type oxygen electrode. The variation of the oxygen concentration in the aqueous solution due to the enzymatic reactions, was measured at a constant applied potential. First of all the response of two biosensors toward standard solutions of methanol, ethanol, n-propanol, n-butanol, ethylenglycol and glycerol was recorded, compared and discussed. In the characterization studies of the biosensors several parameters such as pH, operational stability, response time, analysis time, measure and calibration repeatability, between-days and between-electrodes calibration reproducibility, linearity, sensitivity and substrate specificity were studied. Finally by using the developed biosensors, the ethanol concentrations of several wine and beer samples were determin

New different enzyme amperometric devices for the determination of ethanol in alcoholic beverages were developed by immobilizing alcohol oxidase or catalase in k-Carrageenan gel layer overlapping an amperometric gaseous diffusion Clark type oxygen electrode. The variation of the oxygen concentration in the aqueous solution due to the enzymatic reactions, was measured at a constant applied potential. First of all the response of two biosensors toward standard solutions of methanol, ethanol, n-propanol, n-butanol, ethylenglycol and glycerol was recorded, compared and discussed. In the characterization studies of the biosensors several parameters such as pH, operational stability, response time, analysis time, measure and calibration repeatability, between-days and between-electrodes calibration reproducibility, linearity, sensitivity and substrate specificity were studied. Finally by using the developed biosensors, the ethanol concentrations of several wine and beer samples were determined and the results, obtained with the two enzyme electrodes, were compared. Precision and accuracy showed by the two methods were similar and the recoveries were greater than 90% for both biosensors. A detailed investigation was carried out concerning the correlation between data found measuring ethanol content of several commercial beverages, both using two devices and among these experimental results and nominal values given by producer firms. Lastly a statistical evaluation of variance by F-test was also performed. The response of the catalase biosensor was not influenced by the presence of the methanol. Therefore the biosensor method using catalase enzyme seemed to be the most suitable, between the two enzyme devices, for a selective and less expensive determination of ethanol in alcoholic beverages.1 st IMEKOFOODS Promoting Objective and Measurable Food