Atmos. Chem. Phys. Discuss., 13, 22487-22534, 2013
www.atmos-chem-phys-discuss.net/13/22487/2013/
doi:10.5194/acpd-13-22487-2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Campholenic aldehyde ozonolysis: a possible mechanism for the formation of specific biogenic secondary organic aerosol constituents
A. Kahnt1,2, Y. Iinuma1, A. Mutzel1, O. Böge1, M. Claeys2, and H. Herrmann1
1Leibniz-Institut für Troposphärenforschung (TROPOS), Permoserstr. 15, Leipzig, 04318, Germany
2Department of Pharmaceutical Sciences, University of Antwerp (Campus Drie Eiken), 2610 Antwerp, Belgium

Abstract. 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 with 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 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, detailed interpretation of mass spectral data, in conjunction with the formation of corresponding DNPH-derivatives.

Citation: Kahnt, A., Iinuma, Y., Mutzel, A., Böge, O., Claeys, M., and Herrmann, H.: Campholenic aldehyde ozonolysis: a possible mechanism for the formation of specific biogenic secondary organic aerosol constituents, Atmos. Chem. Phys. Discuss., 13, 22487-22534, doi:10.5194/acpd-13-22487-2013, 2013.
 
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