AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Characterization of Organic Aerosol Using Electrospray Ionization Coupled to Ion Mobility Spectrometry High-Resolution Time-of-Flight Mass Spectrometry (ESI-IMS-HR-TOFMS)
JASON SURRATT, Ying-Hsuan Lin, Joel Kimmel, Manjula Canagaratna, Richard Knochenmuss, Douglas Worsnop, University of North Carolina at Chapel Hill
Abstract Number: 659 Working Group: Instrumentation and Methods
Abstract Organic aerosol (OA) has chemical properties comparable to that of the metabolome. Specifically, both have organic constituents with molecular weights below 1,000 Daltons containing numerous isomers and isobars with varying polarities and functional groups. As a result of this complexity, the full chemical characterization of both systems is a tremendous challenge when using existing analytical techniques such as reverse-phase liquid chromatography (LC) coupled to ESI-MS. Recent work in metabolomics has utilized ion mobility spectrometry (IMS) coupled to ESI-MS for the chemical characterization of small organic compounds similar to those constituting OA. These applications demonstrate the method’s rapid multidimensional separation capabilities and suggest its potential for increasing our knowledge on OA composition and formation mechanisms. IMS portion of this technique separates ions on the basis of their size/charge ratios and their interactions with buffer gases on millisecond time scales. This is analogous to LC or GC techniques; however, these traditional approaches require longer acquisition times. Importantly, during this presentation we will demonstrate the advantages of ESI-IMS-HR-TOFMS over existing off-line techniques for the chemical characterization of fine OA samples collected from both smog chamber and field studies. These advantages include: (1) separation of isobaric and isomeric OA constituents (2) improved chromatographic resolution relative to LC; (3) identification of water-soluble OA constituents not resolved by LC; (4) controlled fragmentation of all parent ions for structural analysis, with no prior knowledge of sample composition (5) improved molecular identification of aerosol constituents via accurate mass analysis of peaks in the high resolution two-dimensional spectra . These advantages demonstrate the possibility of developing ESI-IMS-HR-TOFMS as an online chemical characterization method for OA studies. Disadvantages of this technique will also be discussed when compared to existing techniques.