Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published September 9, 2015 | public
Journal Article

Time-resolved molecular characterization of organic aerosols by PILS + UPLC/ESI-Q-TOFMS


Real-time and quantitative measurement of particulate matter chemical composition represents one of the most challenging problems in the field of atmospheric chemistry. In the present study, we integrate the Particle-into-Liquid Sampler (PILS) with Ultra Performance Liquid Chromatography/Electrospray ionization Quadrupole Time-of-Flight High-Resolution/Mass Spectrometry (UPLC/ESI-Q-TOFMS) for the time-resolved molecular speciation of chamber-derived secondary organic aerosol (SOA). The unique aspect of the combination of these two well-proven techniques is to provide quantifiable molecular-level information of particle-phase organic compounds on timescales of minutes. We demonstrate that the application of the PILS + UPLC/ESI-Q-TOFMS method is not limited to water-soluble inorganic ions and organic carbon, but is extended to slightly water-soluble species through collection efficiency calibration together with sensitivity and linearity tests. By correlating the water solubility of individual species with their O:C ratio, a parameter that is available for aerosol ensembles as well, we define an average aerosol O:C ratio threshold of 0.3, above which the PILS overall particulate mass collection efficiency approaches ∼0.7. The PILS + UPLC/ESI-Q-TOFMS method can be potentially applied to probe the formation and evolution mechanism of a variety of biogenic and anthropogenic SOA systems in laboratory chamber experiments. We illustrate the application of this method to the reactive uptake of isoprene epoxydiols (IEPOX) on hydrated and acidic ammonium sulfate aerosols.

Additional Information

© 2015 Elsevier Ltd. Received 29 May 2015; Received in revised form 18 August 2015; Accepted 18 August 2015; Available online 28 August 2015. Chemical Characterization of Secondary Organic Aerosol - Dedication to Professor Claeys This study was supported by Office of Naval Research grant N00014-14-1-0097.

Additional details

August 22, 2023
October 24, 2023