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| Titel |
Comparison of advanced offline and in situ techniques of organic aerosol composition measurement during the CalNex campaign |
| VerfasserIn |
J. Timkovsky, A. W. H. Chan, T. Dorst, A. H. Goldstein, B. Oyama, R. Holzinger |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 12 ; Nr. 8, no. 12 (2015-12-10), S.5177-5187 |
| Datensatznummer |
250116720
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| Publikation (Nr.) |
 copernicus.org/amt-8-5177-2015.pdf |
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| Zusammenfassung |
| Our understanding of formation processes, physical properties, and
climate/health effects of organic aerosols is still limited in part due to
limited knowledge of organic aerosol composition. We present speciated
measurements of organic aerosol composition by two methods: in situ
thermal-desorption proton-transfer-reaction mass spectrometry (TD-PTR-MS) and
offline two-dimensional gas chromatography with a time-of-flight mass
spectrometer (GC × GC/TOF-MS). Using
the GC × GC/TOF-MS 153 compounds were identified, 123 of which were matched with 64 ions observed
by the TD-PTR-MS. A reasonable overall correlation of 0.67 (r2) was
found between the total matched TD-PTR-MS signal (sum of 64 ions) and the
total matched GC × GC/TOF-MS signal (sum of 123 compounds) for the
Los Angeles area. A reasonable quantitative agreement between the two methods
was observed for most individual compounds with concentrations which were
detected at levels above 2 ng m−3 using the GC × GC/TOF-MS.
The analysis of monocarboxylic acids standards with TD-PTR-MS showed that
alkanoic acids with molecular masses below 290 amu are detected well
(recovery fractions above 60 %). However, the concentrations of these
acids were consistently higher on quartz filters (quantified offline by
GC × GC/TOF-MS) than those suggested by in situ TD-PTR-MS
measurements, which is consistent with the semivolatile nature of the acids
and corresponding positive filter sampling artifacts. |
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