Biochemical sniffer for odourless hydrogen peroxide vapour

A biochemical gas-sensor (bio-sniffer) was constructed for convenient measurement of odourless hydrogen peroxide (H₂O₂) vapour, which is harmful to skin and mucous membranes. An enzyme-immobilized membrane was fabricated by spreading the mixture of catalase and photo-crosslinkable polymer on a dialysis membrane. An H₂O₂ biosensor was constructed by attaching this catalase-immobilized membrane to the sensitive top of a Clark-type oxygen electrode, and the oxygen generation from the decomposition of H₂O₂ catalysed by catalase was measured amperometrically. This biosensor was first applied to the measurement of H₂O₂ solution and was able to quantify the concentrations of H₂O₂ solution from 0.02 to 10.0 mmol L^–1. Then, this biosensor was applied to gaseous phase as a bio-sniffer and was able to detect the odourless H₂O₂ vapour with the calibration range from 0.5 to 30 ppm, where the threshold limit value assigned by the American Conference of Governmental Industrial Hygienists (1 ppm) is covered.