Simultaneous spectrofluorimetric determination of glycerol and ethanol in wine by flow injection using immobilized enzymes

Abstract

An automatic spectrofluorimetric method for the simultaneous determination of glycerol and ethanol is presented. The method is based on the use of a flow injection (FI) manifold and dehydrogenase enzyme immobilized on controlled-pore glass. The proposed method allows for the simultaneous determination of glycerol (linear range between 1 and 10 µg ml^–1, r= 0.9989 and s_r <1%) and ethanol (linear range between 10 and 100 µg ml^–1, r= 0.9998 and s_r <0.9%). It was applied to the determination of both analytes in different wines with recoveries between 97 and 105%. The sampling frequency was 60 samples h^–1. The results obtained on eight wines were compared with those provided by conventional methods and the agreement between them corroborated the usefulness of the proposed method.