Review status: a revised version of this preprint was accepted for the journal AMT.
Measurement of iodine species and sulfuric acid using bromide
chemical ionization mass spectrometers
Mingyi Wang1,2,,Xu-Cheng He3,,Henning Finkenzeller4,Siddharth Iyer3,Dexian Chen1,5,Jiali Shen3,Mario Simon6,Victoria Hofbauer1,2,Jasper Kirkby6,7,Joachim Curtius6,Norbert Maier8,Theo Kurtén3,8,Douglas R. Worsnop3,9,Markku Kulmala3,10,11,12,Matti Rissanen3,13,Rainer Volkamer4,Yee Jun Tham3,Neil M. Donahue1,2,5,14,and Mikko Sipilä3Mingyi Wang et al.Mingyi Wang1,2,,Xu-Cheng He3,,Henning Finkenzeller4,Siddharth Iyer3,Dexian Chen1,5,Jiali Shen3,Mario Simon6,Victoria Hofbauer1,2,Jasper Kirkby6,7,Joachim Curtius6,Norbert Maier8,Theo Kurtén3,8,Douglas R. Worsnop3,9,Markku Kulmala3,10,11,12,Matti Rissanen3,13,Rainer Volkamer4,Yee Jun Tham3,Neil M. Donahue1,2,5,14,and Mikko Sipilä3
1Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
2Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
3Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, 00014 Helsinki, Finland
4Department of Chemistry & CIRES, University of Colorado Boulder, Boulder, CO 80309, USA
5Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
6Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
7CERN, the European Organization for Nuclear Research, CH-1211 Geneve 23, Switzerland
8Department of Chemistry, University of Helsinki, 00014 Helsinki, Finland
9Aerodyne Research, Inc., Billerica, MA, 01821, USA
10Helsinki Institute of Physics, P.O. Box 64 (Gustaf Hallstromin katu 2), FI-00014 University of Helsinki, Finland
11Joint International Research Laboratory of Atmospheric and Earth System Sciences, Nanjing University, Nanjing, China
12Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, China
13Aerosol Physics Laboratory, Physics Unit, Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
14Department of Engineering and Public Policy, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
These authors contributed equally to this work.
1Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
2Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
3Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, 00014 Helsinki, Finland
4Department of Chemistry & CIRES, University of Colorado Boulder, Boulder, CO 80309, USA
5Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
6Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
7CERN, the European Organization for Nuclear Research, CH-1211 Geneve 23, Switzerland
8Department of Chemistry, University of Helsinki, 00014 Helsinki, Finland
9Aerodyne Research, Inc., Billerica, MA, 01821, USA
10Helsinki Institute of Physics, P.O. Box 64 (Gustaf Hallstromin katu 2), FI-00014 University of Helsinki, Finland
11Joint International Research Laboratory of Atmospheric and Earth System Sciences, Nanjing University, Nanjing, China
12Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, China
13Aerosol Physics Laboratory, Physics Unit, Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
14Department of Engineering and Public Policy, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
Received: 15 Dec 2020 – Accepted for review: 15 Dec 2020 – Discussion started: 18 Dec 2020
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 bromide chemical ionization mass spectrometers (Br-CIMS) to this task. During iodine new-particle formation experiments in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber, we have measured gas-phase iodine species and sulfuric acid using two Br-CIMS, 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 inter-comparisons with other instruments attached to the CLOUD chamber, we have quantified the sensitivities of the Br-MION-CIMS to HOI, I2, and H2SO4 and obtain detection limits of 5.8 × 106, 6.3 × 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 one order of magnitude higher than those in the Br-MION-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.
Atmospheric iodine species are often short-lived with low abundance, thus have been challenging to measure. We show that the bromide chemical ionization mass spectrometry, compatible with both the atmospheric pressure and the reduced pressure interfaces, can simultaneously detect various gas-phase iodine species. Combining calibration experiments and quantum chemical calculations, we quantify detection sensitivities to HOI, HIO3, I2, and H2SO4, giving detection limits down to < 106 molec cm−3.
Atmospheric iodine species are often short-lived with low abundance, thus have been challenging...