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Effect of relative humidity on the detection of sulfur dioxide and sulfuric acid using a chemical ionization mass spectrometer

Salcedo, D. and Villalta, P. W. and Varutbangkul, V. and Wormhoudt, J. C. and Miake-Lye, R. C. and Worsnop, D. R. and Ballenthin, J. O. and Thorn, W. F. and Viggiano, A. A. and Miller, T. M. and Flagan, R. C. and Seinfeld, J. H. (2004) Effect of relative humidity on the detection of sulfur dioxide and sulfuric acid using a chemical ionization mass spectrometer. International Journal of Mass Spectrometry, 231 (1). pp. 17-30. ISSN 1387-3806. doi:10.1016/j.ijms.2003.09.005.

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Detection of sulfur dioxide and sulfuric acid at high relative humidity was studied using a chemical ionization mass spectrometer (CIMS). The reactant ions used in the experiments are CO_3^−·nH_2O (n=0–5), which react with SO_2 to form SO_5^−·nH_2O (n=0–2). H_2SO_4 reacts with the precursor ions to form HSO_4^− (m/z=97 amu) and H_2SO_4·CO_3^− (m/z=158 amu). We report the first use of the latter ionization scheme to detect sulfuric acid. High RH affects the detection of SO_2 and H_2SO_4 by forming clusters with the reactant and product ions, reducing sensitivity. Increasing the temperature breaks these clusters. For SO_2 at high RH, either SO_5^− (m/z=112 amu) or SO_5^−·H_2O (m/z=130 amu) can be used for SO_2 detection without a decrease in sensitivity. For H_2SO_4 at high RH, it is preferred to detect the ion H_2SO_4·CO_3^− because the background signal at 158 amu is small, and a better sensitivity can be achieved.

Item Type:Article
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URLURL TypeDescription
Worsnop, D. R.0000-0002-8928-8017
Flagan, R. C.0000-0001-5690-770X
Seinfeld, J. H.0000-0003-1344-4068
Additional Information:© 2003 Elsevier. Received 9 June 2003; accepted 5 September 2003. We appreciate the assistance from personnel of the Air Force Research Laboratory: J. Borghetti, and F. Federico. We thank Jonathan O. Allen for providing us with the impinger model. This work was supported by Office of Naval Research contract N00014-97-C-0254 and grant N00014-96-1-0119, and by Aerodyne Research IR&D funds. We thank R.T. Bluth of the Naval Postgraduate School, R.J. Ferek of the Office on Naval Research, and C.E. Kolb of Aerodyne Research for their support.
Funding AgencyGrant Number
Office of Naval Research (ONR)N00014-97-C-0254
Office of Naval Research (ONR)N00014-96-1-0119
Aerodyne ResearchUNSPECIFIED
Subject Keywords:Chemical ionization mass spectrometer; Sulfur dioxide; Sulfuric acid; Water clusters; Relative humidity
Issue or Number:1
Record Number:CaltechAUTHORS:20150818-172232846
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59757
Deposited By: Irina Meininger
Deposited On:19 Aug 2015 16:32
Last Modified:10 Nov 2021 22:25

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