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Understanding Gas Phase Ion Chemistry Is the Key to Reliable Selected Ion Flow Tube-Mass Spectrometry Analyses
David Smith1, Murray J McEwan2, Patrik Španěl1
1J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 18223 Prague 8, Czech Republic.
Analytical Chemistry
|August 29, 2020
Summary
Ion-molecule reactions are key to trace gas analysis using chemical ionization mass spectrometry. Understanding these reactions is crucial for accurate analysis of humid gases like air and breath.
Area of Science:
- Analytical Chemistry
- Physical Chemistry
Background:
- Ion-molecule reactions (IMR) are fundamental to modern chemical ionization (CI) mass spectrometry.
- CI-MS instruments are widely applied in research and industry for trace gas analysis.
Purpose of the Study:
- This perspective focuses on the ion chemistry governing gas-phase analytical CI methods.
- Special attention is given to selected ion flow tube-mass spectrometry (SIFT-MS).
Main Methods:
- Discussion of ion chemistry processes for key reagent ions: cations (H3O+, NO+, O2+•) and anions (O-•, O2-•, OH-, NO2-).
- Emphasis on the necessity of understanding these processes for reliable analysis of humid gaseous media.
Main Results:
- Detailed examination of ion-molecule reaction mechanisms in CI-MS.
- Highlights the importance of reagent ion chemistry for accurate trace gas quantification.
Conclusions:
- A thorough grasp of ion chemistry is mandatory for reliable analysis of humid samples like ambient air and exhaled breath.
- Further research is required to evaluate the impact of using nitrogen instead of helium as a carrier gas in SIFT-MS.
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