TY - JOUR
T1 - Hydroxydicarboxylic acids: Markers for secondary organic aerosol from the photooxidation of α-pinene
AU - Claeys, M.
AU - Szmigielski, R.
AU - Kourtchev, I.
AU - Van Der Veken, P.
AU - Vermeylen, R.
AU - Maenhaut, W.
AU - Jaoui, M.
AU - Kleindienst, T.E.
AU - Lewandowski, M.
AU - Offenberg, J.H.
AU - Edney, E.O.
PY - 2007/1/23
Y1 - 2007/1/23
N2 - Detailed organic analysis of fine (PM2.5) rural aerosol collected during summer at K-puszta, Hungary from a mixed deciduous/coniferous forest site shows the presence of polar oxygenated compounds that are also formed in laboratory irradiated α-pinene/NOx/air mixtures. In the present work, two major photooxidation products of α-pinene were characterized as the hydroxydicarboxylic acids, 3-hydroxyglutaric acid, and 2-hydroxy-4-isopropyladipic acid, based on chemical, chromatographic, and mass spectral data. Different types of volatile derivatives, including trimethylsilyl ester/ether, methyl ester trimethylsilyl ether, and ethyl ester trimethylsilyl ether derivatives were measured by gas chromatography/mass spectrometry (GC/MS), and their electron ionization (EI) spectra were interpreted in detail. The proposed structures of the hydroxydicarboxylic acids were confirmed or supported with reference compounds. 2-Hydroxy-4-isopropyladipic acid formally corresponds to a further reaction product of pinic acid involving addition of a molecule of water and opening of the dimethylcyclobutane ring; this proposal is supported by a laboratory irradiation experiment with α-pinene/NOx/air. In addition, we report the presence of a structurally related minor α-pinene photooxidation product, which was tentatively identified as the C7 homolog of 3-hydroxyglutaric acid, 3-hydroxy-4,4-dimethylglutaric acid. The detection of 2-hydroxy-4-isopropyladipic acid in ambient aerosol provides an explanation for the relatively low atmospheric concentrations of pinic acid found during daytime in forest environments.
AB - Detailed organic analysis of fine (PM2.5) rural aerosol collected during summer at K-puszta, Hungary from a mixed deciduous/coniferous forest site shows the presence of polar oxygenated compounds that are also formed in laboratory irradiated α-pinene/NOx/air mixtures. In the present work, two major photooxidation products of α-pinene were characterized as the hydroxydicarboxylic acids, 3-hydroxyglutaric acid, and 2-hydroxy-4-isopropyladipic acid, based on chemical, chromatographic, and mass spectral data. Different types of volatile derivatives, including trimethylsilyl ester/ether, methyl ester trimethylsilyl ether, and ethyl ester trimethylsilyl ether derivatives were measured by gas chromatography/mass spectrometry (GC/MS), and their electron ionization (EI) spectra were interpreted in detail. The proposed structures of the hydroxydicarboxylic acids were confirmed or supported with reference compounds. 2-Hydroxy-4-isopropyladipic acid formally corresponds to a further reaction product of pinic acid involving addition of a molecule of water and opening of the dimethylcyclobutane ring; this proposal is supported by a laboratory irradiation experiment with α-pinene/NOx/air. In addition, we report the presence of a structurally related minor α-pinene photooxidation product, which was tentatively identified as the C7 homolog of 3-hydroxyglutaric acid, 3-hydroxy-4,4-dimethylglutaric acid. The detection of 2-hydroxy-4-isopropyladipic acid in ambient aerosol provides an explanation for the relatively low atmospheric concentrations of pinic acid found during daytime in forest environments.
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33847650823&partnerID=MN8TOARS
U2 - 10.1021/es0620181
DO - 10.1021/es0620181
M3 - Article
SN - 0013-936X
VL - 41
SP - 1628
EP - 1634
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 5
ER -