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On-line measurement of the absolute humidity of air, breath and liquid headspace samples by selected ion flow tube mass spectrometry.
Rapid Commun Mass Spectrom. 2001; 15(8):563-9.RC

Abstract

We describe how selected ion flow tube mass spectrometry (SIFT-MS) can be used to determine the absolute humidity of air, breath and liquid headspace samples. This involves the determination of the relative count rates of the H3O+ ions and those H3O+.(H2O)(1,2,3) hydrate ions that inevitably form in the helium carrier gas when humid samples are being analysed by SIFT-MS using H3O+ precursor ions. This requires an understanding of the kinetics of hydrated hydronium ion formation, the involvement of mass discrimination in the analytical quadrupole mass spectrometer and the decreased diffusive loss of the heavier hydrates along the flow tube. Thus, we show that the humidity of breath and liquid headspace samples, typically at the few percent level, can be directly obtained on-line to the SIFT-MS instrument along with the concentrations of trace gases, which are present at much lower levels. We emphasise the value of parallel humidity measurements in ensuring good real-time sampling of breath and liquid headspace and the value of such measurements to trace gas analysis using SIFT-MS.

Authors+Show Affiliations

V. Cermák Laboratory, J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague 8, Czech Republic.No affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

11312505

Citation

Spanĕl, P, and D Smith. "On-line Measurement of the Absolute Humidity of Air, Breath and Liquid Headspace Samples By Selected Ion Flow Tube Mass Spectrometry." Rapid Communications in Mass Spectrometry : RCM, vol. 15, no. 8, 2001, pp. 563-9.
Spanĕl P, Smith D. On-line measurement of the absolute humidity of air, breath and liquid headspace samples by selected ion flow tube mass spectrometry. Rapid Commun Mass Spectrom. 2001;15(8):563-9.
Spanĕl, P., & Smith, D. (2001). On-line measurement of the absolute humidity of air, breath and liquid headspace samples by selected ion flow tube mass spectrometry. Rapid Communications in Mass Spectrometry : RCM, 15(8), 563-9.
Spanĕl P, Smith D. On-line Measurement of the Absolute Humidity of Air, Breath and Liquid Headspace Samples By Selected Ion Flow Tube Mass Spectrometry. Rapid Commun Mass Spectrom. 2001;15(8):563-9. PubMed PMID: 11312505.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - On-line measurement of the absolute humidity of air, breath and liquid headspace samples by selected ion flow tube mass spectrometry. AU - Spanĕl,P, AU - Smith,D, PY - 2001/4/20/pubmed PY - 2001/4/20/medline PY - 2001/4/20/entrez SP - 563 EP - 9 JF - Rapid communications in mass spectrometry : RCM JO - Rapid Commun Mass Spectrom VL - 15 IS - 8 N2 - We describe how selected ion flow tube mass spectrometry (SIFT-MS) can be used to determine the absolute humidity of air, breath and liquid headspace samples. This involves the determination of the relative count rates of the H3O+ ions and those H3O+.(H2O)(1,2,3) hydrate ions that inevitably form in the helium carrier gas when humid samples are being analysed by SIFT-MS using H3O+ precursor ions. This requires an understanding of the kinetics of hydrated hydronium ion formation, the involvement of mass discrimination in the analytical quadrupole mass spectrometer and the decreased diffusive loss of the heavier hydrates along the flow tube. Thus, we show that the humidity of breath and liquid headspace samples, typically at the few percent level, can be directly obtained on-line to the SIFT-MS instrument along with the concentrations of trace gases, which are present at much lower levels. We emphasise the value of parallel humidity measurements in ensuring good real-time sampling of breath and liquid headspace and the value of such measurements to trace gas analysis using SIFT-MS. SN - 0951-4198 UR - https://www.unboundmedicine.com/medline/citation/11312505/On_line_measurement_of_the_absolute_humidity_of_air_breath_and_liquid_headspace_samples_by_selected_ion_flow_tube_mass_spectrometry_ L2 - https://doi.org/10.1002/rcm.265 DB - PRIME DP - Unbound Medicine ER -
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