Analysis of volatile sulphur compounds in breath by gas chromatography-mass spectrometry using a three-stage cryogenic trapping preconcentration system
N. Ochiai et al., Analysis of volatile sulphur compounds in breath by gas chromatography-mass spectrometry using a three-stage cryogenic trapping preconcentration system, J CHROMAT B, 762(1), 2001, pp. 67-75
A method for the determination of trace volatile sulphur compounds (VSCs) i
ncluding methanethiol, dimethyl sulfide (DMS) and dimethyl disulfide (DMDS)
at low ppbv (volume/volume) in breath has been developed using a large vol
ume preconcentration technique prior to capillary GC-MS analysis. The breat
h sample was collected in a 6-l fused-silica-lined stainless steel canister
and introduced into the three-stage cryogenic trapping preconcentration sy
stem by GC-MS in the total ion monitoring (scan) mode. The water condensati
on effect of breath sample inside the canister, which is due to the differe
nce between human body temperature and laboratory temperature, was examined
. The condensed water in the fused-silica-lined canister at 24 degreesC did
not affect the recoveries of VSCs within 12 h. As this three-stage cryogen
ic trapping preconcentration. technique made it possible to remove excess w
ater {relative humidity (RH) > 95%} and carbon dioxide (3.8%) without loss
of the VSCs, more than 400 ml of the breath sample could be concentrated. T
he detection limits of methanethiol, DMS and DMDS in a breath sample using
this method were 0.13, 0.09 and 0.15 ppbv, respectively. (C) 2001 Elsevier
Science B.V. All rights reserved.