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Selected Ion Flow-Drift Tube Mass Spectrometry: Quantification of Volatile Compounds in Air and Breath
- 1.0454143 - ÚFCH JH 2016 RIV US eng J - Journal Article
Spesyvyi, Anatolii - Smith, D. - Španěl, Patrik
Selected Ion Flow-Drift Tube Mass Spectrometry: Quantification of Volatile Compounds in Air and Breath.
Analytical Chemistry. Roč. 87, č. 24 (2015), s. 12151-12160. ISSN 0003-2700
R&D Projects: GA ČR GA13-28882S
Institutional support: RVO:61388955
Keywords : TRACE GAS-ANALYSIS * SIFT-MS * PTR-MS
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 5.886, year: 2015
A selected ion flow-drift tube mass spectrometric analytical technique, SIFDT-MS, is described that extends the established selected ion flow tube mass spectrometry, SIFT-MS, by the inclusion of a static but variable E-field along the axis of the flow tube reactor in which the analytical ion molecule chemistry occurs. The ion axial speed is increased in proportion to the reduced field strength E/N (N is the carrier gas number density), and the residence/reaction time, t, which is measured by Hadamard transform multiplexing, is correspondingly reduced. To ensure a proper understanding of the physics and ion chemistry underlying SIFDT-MS, ion diffusive loss to the walls of the flow-drift tube and the mobility of injected H3O+ ions have been studied as a function of E/N. It is seen that the derived diffusion coefficient and mobility of H3O+ ions are consistent with those previously reported. The rate coefficient has been determined at elevated E/N for the association reaction of the H3O+ reagent ions with H2O molecules, which is the first step in the production of H3O+(H2O)(1,2,3) reagent hydrate ions. The production of hydrated analyte ion was also experimentally investigated. The analytical performance of SIFDT-MS is demonstrated by the quantification of acetone and isoprene in exhaled breath. Finally, the essential features of SIFDT-MS and SIFT-MS are compared, notably pointing out that a much lower speed of the flow-drive pump is required for SIFDT-MS, which facilitates the development of smaller cost-effective analytical instruments for real time breath and fluid headspace analyses.
Permanent Link: http://hdl.handle.net/11104/0254847