title: Laboratory studies of carbon kinetic isotope effects on the production mechanism of particulate phenolic compounds formed by toluene photooxidation: a tool to constrain reaction pathways.
abstract: In this study, we examined compound-specific stable carbon isotope ratios for phenolic compounds in secondary organic aerosol (SOA) formed by photooxidation of isotope-label-free toluene. SOA generated by photooxidation of toluene using a continuous-flow reactor and an 8 m(3) indoor smog chamber was collected on filters, which were extracted with acetonitrile for compound-specific analysis. Eight phenolic compounds were identified in the extracts using a gas chromatograph coupled with a mass spectrometer, and their compound-specific stable carbon isotope ratios were determined using a gas chromatograph coupled with a combustion furnace followed by an isotope ratio mass spectrometer. The majority of products, including methylnitrophenols and methylnitrocatechols, were isotopically depleted by 5-6‰ compared to the initial isotope ratio of toluene, whereas the isotope ratio for 4-nitrophenol remained identical to that of toluene. On the basis of the reaction mechanisms proposed in previous reports, stable carbon isotope ratios of these products were calculated. By comparing the observed isotope ratios with the predicted isotope ratios, we explored possible production pathways for the particulate phenolic compounds.
authors.affiliation: Centre for Atmospheric Chemistry and Department of Chemistry, York University , 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Irei
authors.forename: Jochen
authors.initials: J
authors.lastname: Rudolph
authors.forename: Lin
authors.initials: L
authors.lastname: Huang
authors.forename: Janeen
authors.initials: J
authors.lastname: Auld
authors.forename: Fabrice
authors.initials: F
authors.lastname: Collin
authors.forename: Donald
authors.initials: D
authors.lastname: Hastie
mesh_terms: D000336:Aerosols / Q000737:chemistry; D002247:Carbon Isotopes; D008401:Gas Chromatography-Mass Spectrometry; D007700:Kinetics; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010636:Phenols / Q000138:chemical synthesis* / Q000737:chemistry; D055668:Photochemical Processes; D014050:Toluene / Q000737:chemistry*
chemical_list: D000336:Aerosols; D002247:Carbon Isotopes; D010636:Phenols; D014050:Toluene