AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Evidence and Quantitation of Aromatic Organosulfates in Ambient Aerosols in Lahore, Pakistan
Shuvashish Kundu, Tauseef Quraishi, Ge Yu, Catalina Suarez, Frank Keutsch, ELIZABETH STONE, University of Iowa
Abstract Number: 733 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Organosulfates are important components of secondary organic aerosol (SOA) in ambient atmospheres, yet their structures, abundances, and formation processes are not well understood. In this study, a new type of organosulfate with an aromatic carbon backbone is identified and quantified in fine particulate matter (PM2.5) in the heavily polluted megacity of Lahore, Pakistan. An authentic standard of benzyl sulfate was synthesized and confirmed the presence of this unique compound in aerosol samples using high-resolution time-of-flight tandem mass spectrometry. Benzyl sulfate was quantified using ultra-performance liquid chromatography (UPLC) with negative electrospray ionization triple quadrupole mass spectrometry (ESI-MS/MS). The highest monthly-average benzyl sulfate concentrations were recorded in January and November 2007 (0.50±0.11 ng m-3), whereas the lowest concentration was observed in July (0.05±0.02 ng m-3). Seasonal trends were consistent with synoptic meteorology, with maxima occurring during the dry season and minima during the monsoonal summer. Matrix effects were evaluated by comparison of results obtained by external calibration and the method of standard addition; a minor deviation was observed (<10%) and matrix effects were determined to be insignificant in benzyl sulfate quantitation. Although benzyl sulfate contributions to organic carbon were relatively small (<0.001%), it may be an important tracer for organosulfates derived from anthropogenic volatile organic compounds.