AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Laboratory Characterization of a Volatility and Polarity Separator (VAPS) for Analysis of Oxidized Organic Aerosol
MICHAEL WALKER, Raul Martinez, Claire Fortenberry, Christopher Oxford, Dhruv Mitroo, Nathan Kreisberg, Brent Williams, Washington University in St. Louis
Abstract Number: 507 Working Group: Instrumentation and Methods
Abstract Currently, gaps in our knowledge concerning the oxidative aging of organic aerosol (OA) limit our understanding of the climate and human health impacts of OA. Despite recent advances in atmospheric organic aerosol measurements, several challenges remain with the in situ measurement of oxidized organic aerosol (OOA). A novel Volatility and Polarity Separator (VAPS) has recently been developed that couples thermal desorption – two-dimensional gas chromatography (TD-GCxGC) with high resolution mass spectrometry. Particularly, some chromatographic resolution has been sacrificed compared to typical GCxGC separations in order to maximize throughput of oxygenated material. Following two initial field campaigns, several modifications have been made to improve VAPS measurements. The traditional GC oven has been replaced by two mini GCs that function equally well as the larger oven, improving portability through minimized instrument size and power consumption. Additionally, monitoring the eluate during the thermal desorption phase allows for detection of OOA that is not traditionally suitable for analysis by GC due to its thermal instability. A series of laboratory studies have been conducted to better determine the capabilities of the VAPS for analysis of OOA. Comparison of OOA analysis with more established methods, including measurements by an aerosol mass spectrometer (AMS) and a thermal desorption aerosol gas chromatograph (TAG), highlights the strengths of each method.