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| Titel |
Atmospheric sulphuric acid and neutral cluster measurements using CI-APi-TOF |
| VerfasserIn |
T. Jokinen, M. Sipilä, H. Junninen, M. Ehn, G. Lönn, J. Hakala, T. Petäjä, R. L. Mauldin, M. Kulmala  , D. R. Worsnop |
| 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 ; 12, no. 9 ; Nr. 12, no. 9 (2012-05-09), S.4117-4125 |
| Datensatznummer |
250011124
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| Publikation (Nr.) |
 copernicus.org/acp-12-4117-2012.pdf |
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| Zusammenfassung |
| The first ambient measurements using nitrate ion based Chemical Ionization
with the Atmospheric Pressure interface Time-Of-Flight mass spectrometer
(CI-APi-TOF) for sulphuric acid and neutral cluster detection are presented.
We have found CI-APi-TOF a highly stable and sensitive tool for molecular
sulphuric acid detection. The lowest limit of detection for sulphuric acid
was determined to be 3.6 × 104 molecules cm−3 for 15 min
averaging. Signals from sulphuric acid clusters up to tetramer containing
ammonia were also obtained but these were found to result from naturally
charged clusters formed by ion induced clustering in the atmosphere during
nucleation. Opposite to earlier studies with cluster mass spectrometers, we
had no indication of neutral clusters. The reason is either less efficient
charging of clusters in comparison to molecular sulphuric acid, or the low
concentration of neutral clusters at our measurement site during these
particular nucleation events. We show that utilizing high resolution mass
spectrometry is crucial in separating the weak sulfuric acid cluster signal
from other compounds. |
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