T APHIC TE

SUMMARY Two amperometric biosensors were used as detection units in liquid chromatography for monitoring the production of fuel ethanol in a fermentation process. Sampling was performed on-line by microdialysis and the dialysate was introduced into a liquid chromatographic (Le) system providing separation of the monosaccharides and the ethanol. The analytes were detected by two carbon paste electrodes based on pyranose oxidase or alcohol oxidase, respectively, coimmobilized with horseradish peroxidase, and operated at -50 mV vs. Ag/AgC1 reference.