Exhalation behavior of four organic substrates and water absorbed by human skin

The simultaneous measurement of several volatile organic compounds and water released from the human skin can be achieved successfully by using a modified gas chromatographic system. After the thumb of each subject was dipped in aqueous solution containing acetone, diethyl ether, ethanol, and toluene, it was dried in the air. Then the thumb attached to the sampling probe for measuring the released gases. It is found that 90% of all these chemical substrates were desorbed after 20 min. The initial exhalation rate factor for each chemical substrate was determined in every subject. Correlation factors of the linear relationships between the initial exhalation rate for hydrophilic substrates (acetone and ethanol) and the total amount of water (TAW) released from the skin were 0.94 and 0.92, respectively. However, the rate of hydrophobic toluene was not dependent on the TAW. Therefore, the exhalation rate of substrates is greatly influenced by both their hydrophilicity and TAW. Additionally, an interesting personal specific character among the 6 subjects was observed on plotting the exhalation rate of organic substrates and water during the elapsed time. With the released water mostly due to insensible perspiration, the exhalation rate of all simultaneous organic substrates decreased monotonically over the elapsed time. On the contrary, when subjects sweated emotionally, the exhalation rate of organic substrates showed some variation, namely a higher of exhalation rate compared to the case of mostly due to insensible perspiration. Therefore, emotionally-induced sweating can enhance the release of organic substrates.