HR: 1340h
AN: A33B-0878    [Abstracts]
TI: Hourly In-Situ Measurements of Organic Aerosol Speciation by Thermal desorption Aerosol GC/MS-FID (TAG): Advances in Calibration Procedures
AU: * Kreisberg, N M
EM: nathan@aerosol.us
AF: Aerosol Dynamics Inc., 935 Grayson St, Berkeley, CA 94710 United States
AU: Williams, B J
EM: brentw@nature.berkeley.edu
AF: University of California at Berkeley, ESPM Dept., 247 Hilgard Hall, Berkeley, CA 94720 United States
AU: Goldstein, A H
EM: ahg@nature.berkeley.edu
AF: University of California at Berkeley, ESPM Dept., 247 Hilgard Hall, Berkeley, CA 94720 United States
AU: Hering, S V
EM: susanne@aerosol.us
AF: Aerosol Dynamics Inc., 935 Grayson St, Berkeley, CA 94710 United States
AB: Thermal desorption Aerosol GC/MS-FID (TAG) provides a novel means of obtaining hourly in-situ measurements of organic aerosol speciation. In a typical chromatogram, hundreds to thousands of organic compounds may be present, making careful compound identification and calibration practices a critical part of obtaining reliable and useful data. This presentation will focus on a series of field calibrations performed during sampling of ambient aerosols using the TAG instrument. TAG couples inertial collection of fine particulates with diameters between 0.1 and 2.5 μm and analysis via gas phase chromatography and mass spectrometry following thermal desorption of a sample. This combined collection and analysis system provides hourly speciation of a wide range of organic compounds that is limited only by the compatibility of the GC column (DB-5MS) and feasible temperature range (50-300 °C). The direct introduction of thermally desorbed species into the GC/MS-FID avoids sample handling artifact concerns and costly analytical sample processing. A modified collection cell was introduced to the system that allows direct, in-situ injections of compound standards to calibrate and monitor the performance of the instrument. An evaluation of this approach is presented using results from UC Berkeley laboratory studies and a 5 week urban aerosol study in Riverside, California conducted July-August, 2005 as part of the Study of Organic Aerosols in Riverside (SOAR) campaign. Examples are given where the retention times of a large selection of compounds used as injection standards assisted in the positive identification and quantitation of organic species in ambient aerosols.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0394 Instruments and techniques
DE: 4801 Aerosols (0305, 4906)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005