AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Gas-Particle Partitioning of Organic Aerosols: Defining the Influence of Surface Interactions on Their Volatility
RICHARD E. COCHRAN, Alena Kubatova, Evguenii I. Kozliak, University of North Dakota
Abstract Number: 187 Working Group: Aerosol Chemistry
Abstract Organic aerosols (OA) and their partitioning into the particle phase has long been a complex problem given the large number of species typically present along the aerosol surface. There has been much agreement that interactions between an organic compound and the aerosol surface decrease the compounds volatility. However, the extent of these “matrix-analyte” interactions is not fully understood, and thus current models may misrepresent the partitioning of OA between the gas and particle phases. In order gain a more accurate representation, experimental values need to be established comparing the thermodynamic influences of the “matrix-analyte” interactions. Therefore in this work vaporization enthalpies of a wide and representative range of OA species were experimentally determined under a variety of conditions. Initial experiments were performed with analytes in the form of neat solutions and analytes spiked to model particles, with vaporization enthalpies determined by using tandem thermogravimetry-differential scanning calorimetry (TGA-DSC). Silica and graphite particles were used to represent polar and non-polar aerosol matrices, respectively. Individual vaporization enthalpies of species in the presence of more complex multi-component matrices (i.e., multi-component model particles and real-world particles) were determined using a thermal desorption/pyrolysis-gas chromatography/mass spectrometry (TD/Py-GC/MS) system.