GAS-PHASE MICROBIOSENSOR FOR MONITORING PHENOL VAPOR AT PPB LEVELS

A microbiosensor capable of measuring very low levels of phenol vapor directly in the gas phase has been constructed. The microbiosensor is based on the enzyme polyphenol oxidase, which catalyzes the oxidation of phenols to catechols and then to quinones, Polyphenol oxidase was immobilized in a glycerol-based gel which did not dehydrate significantly over time. An interdigitated microelectrode array was used as transducer. Phenol vapor partitioned into the glycerol gel, where it was enzymatically oxidized to quinone. Signal amplification was achieved by redox recycling of the quinone/catechol couple, This redox recycling produced a biosensor capable of measuring phenol vapor concentrations of 30 ppb. The biosensor produced a constant signal after 5 days of continuous use at room temperature and has potential application in the held of health and safety monitoring, where its ease of use, selectivity, and realtime monitoring would provide personnel with accurate data.