AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Time Resolved Molecular Characterization of Water-Soluble Organic Aerosols by PILS + UPLC/ESI-ToF/MS
XUAN ZHANG, Nathan Dalleska, Dan D. Huang, Kelvin Bates, Armin Sorooshian, Richard Flagan, John Seinfeld, Caltech
Abstract Number: 32 Working Group: Instrumentation and Methods
Abstract We introduce a combination of two techniques, Particle into Liquid Sampler (PILS) and Ultra Performance Liquid Chromatography/Electrospray Ionization Time-of-Flight High-Resolution Mass Spectrometry (UPLC/ESI-ToF/MS), for time-revolved molecular-level characterization of SOA formation and evolution during laboratory chamber experiments. This technique is particularly suited to polar or water-soluble organic molecules, and potentially high molecular weight species. Advantages of this technique mainly include: 1) Molecular-level quantification of particle-phase constituents is available and 2) Temporal profiles of particle composition can be obtained on a time scale consistent with that of SOA evolution. We demonstrate that the PILS+UPLC/ESI-ToF/MS method is suitable to measure water-soluble organic carbon (WSOC), as well as less hydrophilic or slightly water-soluble compounds. A collection efficiency of > 0.6 can be achieved for chamber-derived SOA systems with average O:C ratios > 0.3. We illustrate the application of this technique to 1) the reactive uptake of isoprene epoxydiols (IEPOX) on wet and acidic ammonium sulfate aerosols and 2) formation of dimer esters from ozonolysis of alpha-pinene.