Kinetic enzymatic determination of glycerol in wine and beer using a sequential injection system with spectrophotometric detection

摘要

A sequential injection system for the automatic determination of glycerol in wine and beer was developed. The method is based on the rate of formation of NADH from the reaction of glycerol and NAD(+) catalyzed by the enzyme glycerol dehydrogenase in solution. The determination of glycerol was performed between 0.3 and 3.0 mmol L-1 (0.028 and 0.276 g L-1), and good repeatability was attained (rsd < 3.6%, n=5) for all samples tested. The determination rate was 54 h(-1), the reagent consumption was only 0.75 mu mol of NAD(+) and 5.4 ng of enzyme per assay, and the waste production was 2.12 mL per assay. Results obtained for samples were in agreement with those obtained with the batch enzymatic method.