Glycerol dehydrogenase based amperometric biosensor for monitoring of glycerol in alcoholic beverages

Biosensors for measurement of glycerol in FIA were constructed using NAD(+)-dependent glycerol dehydrogenase (GlDH) either co-immobilized with phenazine methosulphate (PMS) or cross-linked to an Os-complex-modified poly(vinylimidazole) redox polymer (PVI(13)dmeOs) using poly(ethyleneglycole) diglycidilether (PEGDGE). The GlDH/PMS sensor was characterized by a linear range of 0.01-1mM glycerol, a sensitivity of 1.83mA/Mcm(2), a detection limit (calculated as three times the signal-to-noise ratio) of 0.9muM, and with 50% residual activity kept after 15h of continuous operation at a sample throughput of 30 injections/h. The redox hydrogel-based biosensors showed the same dynamic range, but improved biosensors characteristics, i.e., a sensitivity of 4.79 mA/Mcm, a detection limit of 0.1 muM, and a signal loss of only 20% after 15h of operation in the same conditions. The optimized biosensor configurations were further used for analysis of glycerol in wine and the obtained results were compared with the ones obtained by spectrophotometrical experiments