「スマートマテリアル」 ＶＯＣ計測のためのホルムアルデヒドガス用酵素電極

Abstract

An enzymatic gas sensor (called “bio-sniffer”) for formaldehyde vapor was constructed by immobilizing formaldehyde dehydrogenase (FALDH) to hydrophilic polytetrafluoroethylene (H-PTFE) membrane with Platinum-coated electrodes. The platinum electrodes (300 nm) were formed by sputter deposition onto both sides of the H-PTFE membrane (thickness=80 μm, pore size=0.2 μm). The oxidation current of NADH (reduction form) being produced by FALDH enzyme reaction with NAD+ (oxidized form) could be measured by amperometric analysis between two Pt electrodes. The bio-sniffer was used to measure formaldehyde vapor with the calibration range from 40 to 3000 ppb, including the maximum permitted concentration of 80 ppb, with high selectivity being attributable to the substrate specificity of FALDH as gas recognition material. By applying the FALDH sniffer for formaldehyde vapor from building timbers, the bio-sniffer could evaluate the concentration of formaldehyde, thus being in agreement with the results in the commercial available detector tube. The bio-sniffer with high gas selectivity would be effective and convenient non-invasive approach to evaluate the formaldehyde concentration in the gas phase.