Identification of organic acids in secondary organic aerosol and the corresponding gas phase from chamber experiments.
Organic acids in the gas and aerosol phase from photooxidation of 1,3,5-trimethylbenzene in the presence of 300 ppb propene and 300 ppb NOx in smog chamber experiments were determined using a wet effluent diffusion denuder/aerosol collector coupled to ion chromatography (IC) with conductivity detection. Behind the IC, the samples were collected using a fraction collector, for identification of unresolved/unidentified organic acids with IC-mass spectrometry (MS). In total, 20 organic acids were found with MS of which 10 were identified. The organic acids identified offline by IC-MS were then further quantified based on the online IC data. The identification was additionally confirmed with gas chromatography-mass spectrometry. At the maximum aerosol concentration, organic acids comprised 20-45% of the total aerosol mass. The method has a detection limit of 10-100 ng/m3 for the identified carboxylic acids.
Fisseha
R
R
Laboratory of Atmospheric Chemistry, Paul Scherrer Institut (PSI), 5232 Villigen PSI, Switzerland.
Dommen
J
J
Sax
M
M
Paulsen
D
D
Kalberer
M
M
Maurer
R
R
Höfler
F
F
Weingartner
E
E
Baltensperger
U
U