AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Chemical Analysis of Organic Aerosols Using Reactive Nanospray Desorption Electrospray Ionization Mass Spectrometry
ALEXANDER LASKIN, Julia Laskin, Sergey Nizkorodov, Pacific Northwest National Laboratory
Abstract Number: 497 Working Group: Aerosol Chemistry
Abstract Nanospray Desorption Electrospray Ionization (nano-DESI) technique integrated with high resolution mass spectrometry (HR-MS) enables molecular‐level analysis of organic aerosol (OA) samples. In nano-DESI, analyte is desorbed into a small volume solvent bridge formed between two capillaries positioned in contact with analyte and enables fast and efficient characterization of OA collected on substrates without sample preparation. We report applications of the nano-DESI/HR-MS approach in a number of our recent studies focused on molecular identification of organic compounds in laboratory and in field collected OA samples. Reactive nano-DESI approach where selected reagent is added to the solvent is used for examining the presence of individual species containing specific functional groups and for their quantification within complex mixtures of OA. Specifically, we use the Girard’s reagent T (GT) to probe and quantify carbonyl compounds in the SOA mixtures. We estimate for the first time the amounts of dimers and trimers in the SOA mixtures. We found that the most abundant dimer in limonene/O3 SOA was detected at 0.5 pg level and the total amount of dimers and trimers in the analyzed sample was 11 pg. Understanding of the OA composition at the molecular level allowed us to identify key aging reactions, including the transformation of carbonyls to imines and carbonyl-imine oligomerization, that may contribute to the formation of brown carbon in the atmosphere.