Variation in volatile organic compounds in the breath of normal humans

We studied the variation in volatile organic compounds (VOCs) in the breath of 50 normal humans, using gas chromatography and mass spectroscopy. An av erage breath sample contained 204.2 VOCs (SD = 19.8, range 157-241). The al veolar gradient of each VOC (abundance in breath minus abundance in air) va ried with rate of synthesis minus rate of clearance. A total of 3481 differ ent VOCs were observed: 1753 with positive alveolar gradients, 1728 with ne gative alveolar gradients. Twenty-seven VOCs were observed in all fifty sub jects. This study confirmed previous reports of wide inter-individual varia tions. Two new findings were the comparatively small variation in total num ber of breath VOCs, and the presence of a 'common core' of breath VOCs in a ll subjects. (C) 1999 Elsevier Science B.V. All rights reserved.