Using collision-induced dissociation to constrain sensitivity of ammonia chemical ionization mass spectrometry ( N H 4 + CIMS) to oxygenated volatile organic compounds.

ABSTRACT: 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 high-resolution 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 N H 4 + CIMS or proton transfer reactions such as for protontransfer-reaction mass spectrometer (PTR-MS). Switching between the modes can be done within 2min. The N H 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) a

SUBMITTER: Zaytsev A 

PROVIDER: S-EPMC7094031 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature