CERN Accelerating science

Article
Title	Measurement of iodine species and sulfuric acid using bromide chemical ionization mass spectrometers
Author(s)	Wang, Mingyi (Carnegie Mellon U.) ; He, Xu-Cheng (Helsinki U.) ; Finkenzeller, Henning (U. Colorado, Boulder) ; Iyer, Siddharth (Helsinki U.) ; Chen, Dexian (Carnegie Mellon U.) ; Shen, Jiali (Helsinki U.) ; Simon, Mario (Frankfurt U.) ; Hofbauer, Victoria (Carnegie Mellon U.) ; Kirkby, Jasper (CERN ; Frankfurt U.) ; Curtius, Joachim (Frankfurt U.) ; Maier, Norbert (Helsinki U.) ; Kurtén, Theo (Helsinki U.) ; Worsnop, Douglas R (Helsinki U. ; Aerodyne Research, Billerica) ; Kulmala, Markku (Helsinki U. ; Nanjing U. ; Beijing U. of Chem. Tech.) ; Rissanen, Matti (Helsinki U. ; Tampere U. of Tech.) ; Volkamer, Rainer (U. Colorado, Boulder) ; Tham, Yee Jun (UIC, Zhuhai ; Helsinki U.) ; Donahue, Neil M (Carnegie Mellon U.) ; Sipilä, Mikko (Helsinki U.)
Publication	2021
Number of pages	16
In:	Atmos. Meas. Tech. 14 (2021) 4187-4202
DOI	10.5194/amt-14-4187-2021
Subject category	Astrophysics and Astronomy
Accelerator/Facility, Experiment	CLOUD
Abstract	Iodine species are important in the marine atmosphere for oxidation and new-particle formation. Understanding iodine chemistry and iodine new-particle formation requires high time resolution, high sensitivity, and simultaneous measurements of many iodine species. Here, we describe the application of a bromide chemical ionization mass spectrometer (Br-CIMS) to this task. During the iodine oxidation experiments in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber, we have measured gas-phase iodine species and sulfuric acid using two BrCIMS, one coupled to a Multi-scheme chemical IONization inlet (Br-MION-CIMS) and the other to a Filter Inlet for Gasses and AEROsols inlet (Br-FIGAERO-CIMS). From offline calibrations and intercomparisons with other instruments, we have quantified the sensitivities of the Br-MIONCIMS to HOI, I2, and H2SO4 and obtained detection limits of 5.8 × 106 , 3.8 × 105 , and 2.0 × 105 molec. cm−3 , respectively, for a 2 min integration time. From binding energy calculations, we estimate the detection limit for HIO3 to be 1.2 × 105 molec. cm−3 , based on an assumption of maximum sensitivity. Detection limits in the Br-FIGAERO-CIMS are around 1 order of magnitude higher than those in the BrMION-CIMS; for example, the detection limits for HOI and HIO3 are 3.3 × 107 and 5.1 × 106 molec. cm−3 , respectively. Our comparisons of the performance of the MION inlet and the FIGAERO inlet show that bromide chemical ionization mass spectrometers using either atmospheric pressure or reduced pressure interfaces are well-matched to measuring iodine species and sulfuric acid in marine environments.
Copyright/License	publication: © Author(s) 2021 (License: CC-BY-4.0)

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