AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Molecular Characterization of Alkyl nitrates in Atmospheric Aerosol by Ion Mobility Mass Spectrometry
XUAN ZHANG, Wen Xu, Andrew Lambe, Michael Cubison, Michael Groessl, Stephan Graf, John Jayne, Douglas Worsnop, Manjula Canagaratna, Aerodyne Research Inc.
Abstract Number: 63 Working Group: Effects of NOx and SO2 on BVOC Oxidation and Organic Aerosol Formation
Abstract We demonstrate the capability of Ion Mobility Mass Spectrometry (IMS-MS) to characterize alkyl nitrates in atmospheric aerosols at molecular level. We show the significant production of ion adducts from selected alkyl nitrate standards by clustering with inorganic anions including chloride and nitrate during negative electrospray ionization, a special chemical ionization mechanism in the condensed phase. This approach enables straightforward detection of ANs that have low tendency to form molecular ions on its own. Molecular identity of each AN adduct is well constrained by the developed collision cross section - mass correlation, which provides a two-dimensional separation of the -ONO2 containing compounds on the basis of their molecular size and geometry. Structural information of alkyl nitrates is further probed by the identification of the characteristic fragments produced from collision induced dissociation of the parent AN adducts. We apply the IMS-MS technique to characterize alkyl nitrates in the secondary organic aerosols produced from photochemistry of biogenic emissions in the presence of NO as an illustration.