Flow-through spectrofluorimetric sensor for the determination of glycerol in wine

Abstract

A flow-through sensor based on transient immobilization of NADH, the product of the reaction between glycerol and NAD⁺ catalysed by glycerol dehydrogenase, is proposed. The biocatalyst is immobilized on controlled-pore glass, where the enzymic reaction takes place, the product of the reaction being transiently retained and spectrofluorimetrically monitored on passage through a flow cell packed with a solid support. The proposed method affords a linear range between 0.3 and 5.0 µg ml^–1 of glycerol, and a detection limit of 0.1 µg ml^–1, with a relative standard deviation of less than 2%. The performance of the sensor was checked by applying it to the determination of glycerol in wine. The results obtained agree well with those provided by a conventional method based on HPLC.