Using collision-induced dissociation to constrain sensitivity of ammonia chemical ionization mass spectrometry (NH 4 + CIMS) to oxygenated volatile organic compounds
Author(s)
Koss, Abigail R.; Lim, Christopher Yung-Ta; Rowe, James Clifford.; Kroll, Jesse![Thumbnail](/bitstream/handle/1721.1/125653/amt-12-1861-2019.pdf.jpg?sequence=4&isAllowed=y)
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Chemical ionization mass spectrometry (CIMS) instruments routinely detect hundreds of oxidized organic compounds in the atmosphere. A major limitation of these instruments is the uncertainty in their sensitivity to many of the detected ions. We describe the development of a new highresolution time-of-flight chemical ionization mass spectrometer that operates in one of two ionization modes: Using either ammonium ion ligand-switching reactions such as for NHC 4 CIMS or proton transfer reactions such as for protontransfer-reaction mass spectrometer (PTR-MS). Switching between the modes can be done within 2 min. The NH+4 CIMS mode of the new instrument has sensitivities of up to 67 000 dcps ppbv..1 (duty-cycle-corrected ion counts per second per part per billion by volume) and detection limits between 1 and 60 pptv at 2σ for a 1 s integration time for numerous oxygenated volatile organic compounds. We present a mass spectrometric voltage scanning procedure based on collision-induced dissociation that allows us to determine the stability of ammonium-organic ions detected by the NH+4 CIMS instrument. Using this procedure, we can effectively constrain the sensitivity of the ammonia chemical ionization mass spectrometer to a wide range of detected oxidized volatile organic compounds for which no calibration standards exist. We demonstrate the application of this procedure by quantifying the composition of secondary organic aerosols in a series of laboratory experiments.
Date issued
2019-03Department
Massachusetts Institute of Technology. Department of Civil and Environmental EngineeringJournal
Atmospheric Measurement Techniques
Publisher
Copernicus GmbH
Citation
Zaytsev, Alexander et al. “Using collision-induced dissociation to constrain sensitivity of ammonia chemical ionization mass spectrometry (NH 4 + CIMS) to oxygenated volatile organic compounds” Atmospheric Measurement Techniques, vol. 12, no. 3, 2019, pp. 1861-1870 © 2019 The Author(s)
Version: Final published version
ISSN
1867-8548
1867-1381