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| Titel |
The effect of H₂SO₄ – amine clustering on chemical ionization mass spectrometry (CIMS) measurements of gas-phase sulfuric acid |
| VerfasserIn |
T. Kurtén, T. Petäjä, J. Smith, I. K. Ortega, M. Sipilä, H. Junninen, M. Ehn, H. Vehkamäki, L. Mauldin, D. R. Worsnop, M. Kulmala  |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 6 ; Nr. 11, no. 6 (2011-03-31), S.3007-3019 |
| Datensatznummer |
250009535
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| Publikation (Nr.) |
 copernicus.org/acp-11-3007-2011.pdf |
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| Zusammenfassung |
| The state-of-the art method for measuring atmospheric gas-phase sulfuric
acid is chemical ionization mass spectrometry (CIMS) based on nitrate
reagent ions. We have assessed the possible effect of the sulfuric acid
molecules clustering with base molecules on CIMS measurements using
computational chemistry. From the computational data, three conclusions can
be drawn. First, a significant fraction of the gas-phase sulfuric acid
molecules are very likely clustered with amines if the amine concentration
is around or above a few ppt. Second, some fraction of these acid-amine
clusters may not be charged by the CIMS instrument, though the most reliable
computational methods employed predict this fraction to be small; on the
order of ten percent or less. Third, the amine molecules will evaporate
practically immediately after charging, thus evading detection. These
effects may need to be taken into account in the interpretation of
atmospheric measurement data obtained using chemical ionization methods. The
purpose of this study is not to criticize the CIMS method, but to help
understand the implications of the measured results. |
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