Quantification of methane in humid air and exhaled breath using selected ion flow tube mass spectrometry

0355628 - ÚFCH JH 2011 RIV GB eng J - Journal Article
Dryahina, Kseniya - Smith, D. - Španěl, Patrik
Quantification of methane in humid air and exhaled breath using selected ion flow tube mass spectrometry.
Rapid Communications in Mass Spectrometry. Roč. 24, č. 9 (2010), s. 1296-1304. ISSN 0951-4198. E-ISSN 1097-0231
R&D Projects: GA ČR GP203/09/P172; GA ČR GA202/09/0800
Institutional research plan: CEZ:AV0Z40400503
Keywords : mass spectrometry * SIFT-MS * breath
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.846, year: 2010

In selected ion flow tube mass spectrometry, SIFT-MS, analyses of humid air and breath, it is essential to consider and account for the influence of water vapour in the media, which can be profound for the analysis of some compounds, including H2CO, H2S and notably CO2. To date, the analysis of methane has not been considered, since it is known to be unreactive with H3O+ and NO+, the most important precursor ions for SIFT-MS analyses, and it reacts only slowly with the other available precursor ion, O-2(+). However, we have now experimentally investigated methane analysis and report that it can be quantified in both air and exhaled breath by exploiting the slow O-2(+)/PCH4 reaction that produces CH3O2+ ions. We show that the ion chemistry is significantly influenced by the presence of water vapour in the sample, which must be quantified if accurate analyses are to be performed.
Permanent Link: http://hdl.handle.net/11104/0006305