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Anal Chem

Title:		"Electrostatic Switching and Selection of H(3)O(+), NO(+), and O(2)(+*) Reagent Ions for Selected Ion Flow-Drift Tube Mass Spectrometric Analyses of Air and Breath"
Author(s):		Spanel P; Spesyvyi A; Smith D;
Address:		"J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences , Dolejskova 3 , 18223 Prague 8 , Czech Republic"
Journal Title:		Anal Chem
Year:		2019
Volume:		20190327
Issue:		8
Page Number:		5380 - 5388
DOI:		10.1021/acs.analchem.9b00530
ISSN/ISBN:		1520-6882 (Electronic) 0003-2700 (Linking)
Abstract:		"Soft chemical ionization mass spectrometry techniques, particularly the well-established proton transfer reaction mass spectrometry, PTR-MS, and selected ion flow tube mass spectrometry, SIFT-MS, are widely used for real-time quantification of volatile organic compounds in ambient air and exhaled breath with applications ranging from environmental science to medicine. The most common reagent ions H(3)O(+), NO(+), or O(2)(+*) can be selected either by quadrupole mass filtering from a discharge ion source, which is relatively inefficient, or by switching the gas/vapor in the ion source, which is relatively slow. The chosen reagent ions are introduced into a flow tube or flow-drift tube reactor where they react with analyte molecules in sample gas. This article describes a new electrostatic reagent ion switching, ERIS, technique by which H(3)O(+), NO(+), and O(2)(+*) reagent ions, produced simultaneously in three separate gas discharges, can be purified in post-discharge source drift tubes, switched rapidly, and selected for transport into a flow-drift tube reactor. The construction of the device and the ion-molecule chemistry exploited to purify the individual reagent ions are described. The speed and sensitivity of ERIS coupled to a selected ion flow-drift tube mass spectrometry, SIFDT-MS, is demonstrated by the simultaneous quantification of methanol with H(3)O(+), acetone with NO(+), and dimethyl sulfide with O(2)(+*) reagent ions in single breath exhalations. The present ERIS approach is shown to be preferable to the previously used quadrupole filtering, as it increases analytical sensitivity of the SIFDT-MS instrument while reducing its size and the required number of vacuum pumps"
Keywords:		Air Body Fluids/*chemistry *Breath Tests Gases/chemistry Humans Indicators and Reagents/*analysis Ions/analysis Mass Spectrometry/instrumentation Nitric Oxide/*analysis Onium Compounds/*analysis Oxygen/*analysis Static Electricity;
Notes:		"MedlineSpanel, Patrik Spesyvyi, Anatolii Smith, David eng Research Support, Non-U.S. Gov't 2019/03/15 Anal Chem. 2019 Apr 16; 91(8):5380-5388. doi: 10.1021/acs.analchem.9b00530. Epub 2019 Mar 27"