AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Heterogeneous Ozonation and Nitration Products of Polycyclic Aromatic Hydrocarbons
RICHARD COCHRAN, Haewoo Jeong, Shokouh H. Haddadi, Alexandra C. Smith, Rebeka F. Derseh, Nagaraju Dongari, Josef Beranek, Alena Kubatova, University of North Dakota
Abstract Number: 262 Working Group: Aerosol Chemistry
Abstract Polycyclic aromatic hydrocarbons (PAHs) have long been known to be mutagenic. Recent toxicological studies have attributed the genotoxicity of particulate matter (PM) to higher polarity species as well, notably nitro-, dinitro, oxy-, and hydroxy-PAH oxidation products. While the gaseous reaction of PAHs in atmospheric processes have been extensively explored, the knowledge regarding the formation of PAH oxidation products through heterogeneous reactions is limited. Typically the most abundant PAHs in PM are semi-volatile species with 3–4 aromatic rings. Therefore, in this work we have studied the heterogenoues nitration and oxygenation of phenanthrene, anthracene, fluoranthene, and pyrene using nitrogen dioxide and ozone. While the reactions have previously been explored the focus of this study was on the detailed identification of reaction products. Several oxidation products with multiple functional groups, including carboxaldehyde, carboxylic acid, and/or hydroxylated species, were identified, especially for reactions of anthracene and pyrene with ozone. These species were also found to form 1-nitropyrene and 9-nitroanthracene upon reaction with nitrogen dioxide. In reactions with both nitrogen dioxide and ozone a broader distribution of oxidation products were observed, most likely due to the in-situ formation of the more powerful oxidant NO3. Detailed identification was confirmed using standards and sequential derivatization of carbonyl and hydroxyl functional groups with pentafluorobenzyl hydroxylamine (PFBHA) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), respectively, followed by gas chromatography-mass spectrometry (GC-MS) analysis. Further identification was confirmed using liquid chromatography with high resolution time of flight MS.