AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Quantification of the Carbonyl Group Contribution to Aqueous-Phase SOA Using Fourier Transform Infrared Spectroscopy
Kathryn George, Travis Ruthenburg, Jeremy Smith, Lu Yu, Cort Anastasio, Qi Zhang, ANN DILLNER, University of California, Davis
Abstract Number: 314 Working Group: Aerosol Chemistry
Abstract Reactions in the aqueous-phase play an important role in atmospheric secondary organic aerosol (SOA) production, yet many of the products remain poorly characterized. Phenols, water-soluble compounds released during biomass combustion, readily participate in aqueous-phase reactions to form low volatility SOA products. In this study, aqueous-phase SOA was produced from the oxidation of three phenolic compounds (phenol, guaiacol, and syringol) by OH and the triplet excited state of 3,4-dimethoxybenzaldehyde. Here, we analyze carbonyl-containing SOA products using a Fourier transform infrared spectroscopic (FTIR) technique.
Aqueous-phase SOA was atomized, collected on a Teflon filter, weighed, and scanned in transmission mode on an FTIR. In order to quantify the carbonyl functional group contribution, we calibrated using carbonyl-containing compounds that included carboxylic acids, a ketone, and an ester, all of which absorb in a wavenumber range similar to that found in our SOA samples. Our results indicate that carbonyl-containing compounds account for up to 11% of the total SOA mass in our samples. Carbonyls are generally present in the greatest amount in syringol SOA, followed by guaiacol and phenol SOA. Ion chromatography on the same samples indicates that only a small fraction of the carbonyls measured by FTIR are small acids. These results provide new insight on carbonyl production in aqueous-phase SOA.