2D spatiotemporal visualization system of expired gaseous ethanol after oral administration for real-time illustrated analysis of alcohol metabolism

A novel 2-dimensional spatiotemporal visualization system of expired gaseous ethanol after oral administration for real-time illustrated analysis of alcohol metabolism has been developed, which employed a low level light CCD camera to detect chemiluminescence (CL) generated by catalytic reactions of standard gaseous ethanol and expired gaseous ethanol after oral administration. First, the optimization of the substrates for visualization and the concentration of luminol solution for CL were investigated. The cotton mesh and 5.0 mmol L⁻¹ luminol solution were selected for further investigations and this system is useful for 0.1-20.0 mmol L⁻¹ of H₂O₂ solution. Then, the effect of pH condition of Tris-HCl buffer solution was also evaluated with CL intensity and under the Tris-HCl buffer solution pH 10.1, a wide calibration range of standard gaseous ethanol (30-400 ppm) was obtained. Finally, expired air of 5 healthy volunteers after oral administration was measured at 15, 30, 45, 60, 75, 90, 105 and 120 min after oral administration, and this system showed a good sensitivity on expired gaseous ethanol for alcohol metabolism. The peaks of expired gaseous ethanol concentration appeared within 30 min after oral administration. During the 30 min after oral administration, the time variation profile based on mean values showed the absorption and distribution function, and the values onward showed the elimination function. The absorption and distribution of expired gaseous ethanol in 5 healthy volunteers following first-order absorption process were faster than the elimination process, which proves efficacious of this system for described alcohol metabolism in healthy volunteers. This system is expected to be used as a non-invasive method to detect VOCs as well as several other drugs 1] in expired air for clinical purpose.