Identification of Organic Nitrates in the NO₃ Radical Initiated Oxidation of α-Pinene by Atmospheric Pressure Chemical Ionization Mass Spectrometry

Journal Article · Wed Jul 07 00:00:00 EDT 2010 · Environmental Science and Technology

DOI:https://doi.org/10.1021/es1005658· OSTI ID:1097993

Perraud, Veronique M.; Bruns, Emily A.; Ezell, Michael J.; Johnson, Stanley N.; Greaves, John; Finlayson-Pitts, Barbara J.

The gas-phase reactions of nitrate radicals (NO₃) with biogenic organic compounds are a major sink for these organics during night-time. These reactions form secondary organic aerosols, including organic nitrates that can undergo long-range transport, releasing NO_x downwind. We report here studies of the reaction of NO₃ with R-pinene at 1 atm in dry synthetic air(relative humidity ~3%) and at 298K using atmospheric pressure chemical ionization triple quadrupole mass spectrometry (APCI-MS) to identify gaseous and particulate products. The emphasis is on the identification of individual organic nitrates in the particle phase that were obtained by passing the product mixture through a denuder to remove gas-phase reactants and products prior to entering the source region of the mass spectrometer. Filter extracts were also analyzed by GCMS and by APCI time-of-flight mass spectrometry (APCI-ToFMS) with methanol as the proton source. In addition to pinonaldehyde and pinonic acid, five organic nitrates were identified in the particles as well as in the gas phase: 3-oxopinane- 2-nitrate, 2-hydroxypinane-3-nitrate, pinonaldehyde-PAN, norpinonaldehyde-PAN, and (3-acetyl-2,2-dimethyl-3-nitrooxycyclobutyl) acetaldehyde. Furthermore, there was an additional first generation organic nitrate product tentatively identified as a carbonyl hydroxynitrate with a molecular mass of 229. These studies suggest that a variety of organic nitrates would partition between the gas phase and particles in the atmosphere, and serve as a reservoir for NO_x.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1097993
• Journal Information: Environmental Science and Technology, Vol. 44, Issue 15; ISSN 0013-936X
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory