“Sniffer-camera” using enzyme reaction for visualization of transpired ethanol from palm skin

An imaging system for gaseous ethanol transpired from human palm skin, based on an enzymatic reaction, was assembled and validated. This system uses a highly sensitive camera that measures gaseous ethanol concentrations as intensities of chemiluminescence from luminol’s reaction induced by alcohol oxidase (AOD) and a luminol-hydrogen peroxide-horseradish peroxidase (HRP) system. Conversion of gaseous ethanol concentrations and distributions proceed on an enzyme-immobilized mesh substrate with luminol solution in a dark box. In order to visualize ethanol transpired from human palm skin, we improved the chemiluminescence sensitivity of the imaging system with a mixture of a high-purity luminol solution of luminol sodium salt HG solution and an enhancer of eosin Y solution. The detection limit of the ethanol concentration was 4.9 ppm. This highly sensitive imaging allows successful visualization of ethanol transpired from palm skin.