ONLINE DETERMINATION OF ETHANOL IN BIOPROCESSES BASED ON SAMPLE EXTRACTION BY CONTINUOUS PERVAPORATION

The development of a flow injection analysis system (FIA) based on imm obilized enzymes for the on-line determination of ethanol in biologica l liquids is presented. The FIA system includes prior to enzymatic ana lysis a continuous purification by pervaporation, which is supplemente d with an electronically controlled temperature device. Fundamental ex periments with the pervaporation module as well as the application of this system for the monitoring of ethanol in beer and during a bakers' yeast cultivation (measurable range 1-100; mM) are presented. The res ults show good reproducibility and satisfactory agreement with those o f a common enzymatic test kit. Incorporation of the pervaporation modu le enhanced the stability of the enzyme noticeably.