Findings of Skin Gases and Their Possibilities in Healthcare Monitoring

We have found several gases emanating from human skin, which we refer to as ‘skin gas’. We collected skin gases from the hands, arms, fingers and other local areas on the human body, and then concentrated them in a cold trap of a 20-cm-long stainless-steel capillary, developed by us, and determined the skin gas components mostly by gas chromatography or gas chromatography/mass spectrometry with online analysis. The skin gases identified are acetone, ethanol, hydrogen, ammonia, methane, nitrogen monoxide, carbon monoxide, rose flavor after intake of essential oils, allylmethyl sulfide after intake of garlic, etc. The concentration of the components in skin gas has a good relationship with to that in blood and in some cases in breath. The variation in levels of ammonia in both skin gas and blood after the intake of protein was examined. It is clear that both the emanating rate of ammonia in the skin gas and the concentration in the blood increased after protein intake, and ammonia concentration reached its maximum level after about 2 h. The acetone concentration in skin gas correlated with the blood β-hydroxybutyrate concentration (r = 0.669). The skin gas acetone concentration was high (940 ppb) in a patient with diabetic ketoacidosis, and it fell to 80 ppb after insulin therapy. Skin gas ethanol was always observed even in healthy subjects without any intake of alcohol.