SIMULTANEOUS SPECTROFLUOROMETRIC DETERMINATION OF GLYCEROL AND ETHANOL IN WINE BY FLOW-INJECTION USING IMMOBILIZED ENZYMES

An automatic spectrofluorimetric method for the simultaneous determina tion of glycerol and ethanol is presented. The method is based on the use of a flow injection (FI) manifold and dehydrogenase enzyme immobil ized on controlled-pore glass. The proposed method allows for the simu ltaneous determination of glycerol (linear range between 1 and 10 mu g ml(-1), r = 0.9989 and s(r) <1%) and ethanol (linear range between 10 and 100 mu g ml(-1), r = 0.9998 and s(r) <0.9%). It was applied to th e determination of both analytes in different wines with recoveries be tween 97 and 105%. The sampling frequency was 60 samples h(-1). The re sults obtained on eight wines were compared with those provided by con ventional methods and the agreement between them corroborated the usef ulness of the proposed method.