Sub-parts per billion detection of trace volatile chemicals in human breath using Selected Ion Flow Tube Mass Spectrometry

Table 1 Levels of trace volatile compounds in alveolar and oral air.

Sample	Compartment	Indole	Methylindole	Hydrogen Sulphide	Methylmercaptan
Ambient	NA	0.4	0	0.4	4
Subject 1	Alveolar	1.7	0.4	10	10
	Oral	2.4	0.8	48	71
Subject 2	Alveolar	2.2	0.4	9.2	9.4
	Oral	3.2	0.9	23	44
Subject 3	Alveolar	1.1	0.9	11	4.3
	Oral	1.7	1.2	41	38

Levels of indole, methylindole (all isomers), hydrogen sulphide and methylmercaptan were measured in ambient air, or in a single alveolar breath or static oral air (approximately 10 second measurement duration) of 3 healthy human subjects by SIFT-MS using characteristic products ions of the reaction with H₃O⁺ precursors. Values are in PPBV. NA: not applicable.

ISSN: 1756-0500