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| Titel |
Campholenic aldehyde ozonolysis: a mechanism leading to specific biogenic secondary organic aerosol constituents |
| VerfasserIn |
A. Kahnt, Y. Iinuma, A. Mutzel, O. Böge, M. Claeys, H. Herrmann |
| 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 ; 14, no. 2 ; Nr. 14, no. 2 (2014-01-22), S.719-736 |
| Datensatznummer |
250118301
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| Publikation (Nr.) |
 copernicus.org/acp-14-719-2014.pdf |
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| Zusammenfassung |
| In the present study, campholenic aldehyde ozonolysis was performed to
investigate pathways leading to specific biogenic secondary organic aerosol
(SOA) marker compounds. Campholenic aldehyde, a known α-pinene
oxidation product, is suggested to be a key intermediate in the formation of
terpenylic acid upon α-pinene ozonolysis. It was reacted with ozone
in the presence and absence of an OH radical scavenger, leading to SOA
formation with a yield of 0.75 and 0.8, respectively. The resulting
oxidation products in the gas and particle phases were investigated
employing a denuder/filter sampling combination. Gas-phase oxidation
products bearing a carbonyl group, which were collected by the denuder, were
derivatised by 2,4-dinitrophenylhydrazine (DNPH) followed by liquid
chromatography/negative ion electrospray ionisation time-of-flight mass
spectrometry analysis and were compared to the gas-phase compounds detected
by online proton-transfer-reaction mass spectrometry. Particle-phase
products were also analysed, directly or after DNPH derivatisation, to
derive information about specific compounds leading to SOA formation. Among
the detected compounds, the aldehydic precursor of terpenylic acid was
identified and its presence was confirmed in ambient aerosol samples from
the DNPH derivatisation, accurate mass data,
and additional mass spectrometry (MS2 and MS3
fragmentation studies). Furthermore, the present investigation sheds light on
a reaction pathway leading to the formation of terpenylic acid, involving
α-pinene, α-pinene oxide, campholenic aldehyde, and
terpenylic aldehyde. Additionally, the formation of diaterpenylic acid
acetate could be connected to campholenic aldehyde oxidation. The present
study also provides insights into the source of other highly functionalised
oxidation products (e.g. m / z 201, C9H14O5 and m / z 215,
C10H16O5), which have been observed in ambient aerosol
samples and smog chamber-generated monoterpene SOA. The m / z 201 and 215
compounds were tentatively identified as a C9- and
C10-carbonyl-dicarboxylic acid, respectively, based on reaction
mechanisms of campholenic aldehyde and ozone, as well as detailed interpretation of
mass spectral data, in conjunction with the formation of corresponding
DNPH derivatives. |
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