A direct gaseous ethanol imaging system for analysis of alcohol metabolism from exhaled breath

A non-invasive breath gaseous ethanol imaging system with an exhaled breath flow rate control has been developed. The system offers straight-forward, rapid, and painless sampling from patients, and can be applied to diagnose diseases. The system provides an image of ethanol concentration using chemiluminescence (CL) from an enzyme-immobilized support. The system measures ethanol concentrations as intensities of CL by luminol reaction induced by alcohol oxidase and horseradish peroxidase–luminol–hydrogen peroxide system. The spatio-temporal change in CL generates by ethanol in an exhaled breath is detected by an electron multiplier EM-CCD camera and analyzed. An ethanol skin patch test, a simple method of indicating aldehydehydrogenase 2 (ALDH2), is performed on healthy volunteers. Breath samples from volunteers with ALDH2(+) and ALDH2(−) are analyzed. The exhaled breath flow rate control unit can control and optimize the naturally unstable flow rate of human breath without a gas sampling bag. The coefficient of variance in the exhaled breath flow rate is estimated at 2.8% at a flow rate of 200 mL/min. Exhaled gaseous ethanol obtained from volunteers is visualized and analyzed over a period of 300 min following the oral administration of ethanol at 0.4 g/kg body weight. A peak in the exhaled breath ethanol concentration appears at 30 min for both ALDH2(+) and ALDH2(−) volunteers, the breath ethanol concentration then gradually decreases over the remainder of the 300 min.