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| Titel |
Analysis of High Mass Resolution PTR-TOF Spectra from 1,3,5-trimethylbenzene (TMB) Smog Chamber Experiments |
| VerfasserIn |
M. Müller, M. Graus, A. Metzger, J. Dommer, A. Wisthaler, A. Hansel |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250028228
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| Zusammenfassung |
| A series of 1,3,5-trimethylbenzene (TMB) photo-oxidation experiments was performed under
various NOx conditions in the 27 m3 Paul Scherrer Institute environmental chamber. Due to
well-defined conditions under which smog chamber experiments can be performed, results
are very valuable for the development and the evaluation of chemical mechanisms and to get
a better understanding of processes leading to secondary organic aerosol (SOA)
formation.
A prototype of a High Resolution Proton Transfer Reaction Time-of-Flight Mass
Spectrometer (PTR-TOF) was applied for on-line VOC analysis. The soft PTR ionization
technique hardly affects the structure of analyzed compounds during ionization. Therefore, a
low amount of fragmentation with almost no loss of carbon and very little loss of oxygen into
a neutral fragment occurs.
Using the PTR-TOF, Â 300 VOCs were found during TMB photo-oxidation experiments and
corresponding time traces were recorded. About 100 VOCs were present with volume mixing
ratios > 0.5 ppbv. Empirical formulas CnHmNpOo were determined and VOCs were
separated and grouped according to their C, O and N numbers. This allowed to determine
photo-oxidation grade dependent values such as the O:C ratio and time traces of mono- and
multi-oxygenated compounds. The results are compared with results predicted by the Master
Chemical Mechanism (MCM). |
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