BIOSENSORS BASED ON CATALASE MEMBRANES WI TH UTILIZATION OF ENZYMATICBIFUNCTIONALITY FOR MOLECULAR-SELECTIVE CARRIER-ANALYSIS OF ETHANOL

A robust bioelectrochemical measuring system for amperometric electroa nalysis of ethanol is presented, which allows measurements between 0.0 1 and 99.8 vol.% of ethanol without preceeding dilution. It is disting uished by long-lived biosensors based on bifunctional catalase membran es. Besides the O-2-sensitive enzymatic biosensor the design includes components for intermediate carrier analysis such as a microdialysator for analyte uptake into buffered, H2O2 containing carrier solution ou t of the sample solution both with tangential countercurrent fluxes, a n oxigenating pump for constant pO(2) in the carrier stream, a pressur e adjusting chamber as protection from variing pressure on the enzyme membrane resulting from the roller pump's pulsations. Utilization of t he membrane's catalatic and peroxidatic bifunctionality is the basis o f ethanol analysis: peroxidatically acting catalase molecules cannot r elease oxygen by catalatic reaction of H2O2 at the same time.