10th International Aerosol Conference
September 2 - September 7, 2018
America's Center Convention Complex
St. Louis, Missouri, USA

Abstract View


Laboratory Evaluation of Organic Aerosol Chemical Composition Measurements Obtained from High-Resolution Mass Spectrometers with Different Soft Ionization Schemes

JORDAN KRECHMER, Andrew Lambe, Felipe Lopez-Hilfiker, John Jayne, Douglas Worsnop, Manjula Canagaratna, Aerodyne Research, Inc.

     Abstract Number: 743
     Working Group: Aerosol Chemistry

Abstract
Atmospheric organic aerosols remain an important topic of study because of their impacts on human health and climate. Historically, our community has lacked aerosol measurement techniques that are can measure a high mass fraction of organic aerosols with high chemical resolution at high time resolution. In attempt to achieve these goals, several techniques have recently been developed that combine soft-ionization and high-resolution time-of-flight mass spectrometry. Here, we discuss applications of a Filter Inlet for Gases and AEROsols coupled to a chemical-ionization mass spectrometer (FIGAERO-CIMS), a heated desorption inlet tube interfaced to a Vocus Proton Transfer Reaction Mass Spectrometer (PTRMS), and extractive electrospray ionization with mass spectrometry (EESI). We obtain simultaneous FIGAERO-CIMS, PTR-MS and EESI-MS measurements of secondary organic aerosol generated in an oxidation flow reactor. We examine the influence of thermal decomposition, chemical fragmentation, and ionization selectivity on FIGAERO-CIMS, PTRMS and EESI-MS measurements. Additional information obtained from the FIGAERO thermograms is assessed. We compare the on-line measurements with off-line electrospray ionization ion mobility mass spectrometry (IMS-MS) analysis, which allows for increased molecular-level identification via isobaric and isomeric separation and collisionally-induced dissociation. The fraction of organic mass characterized by these techniques is evaluated by comparison with organic mass concentrations obtained with an aerosol mass spectrometer.