HR: 0800h
AN: A51B-0052    [Abstracts]
TI: Biogenic VOC Emissions Measured by Solid Phase Microextraction (SPME) Fibers, Proton Transfer Reaction Mass Spectrometry (PTR-MS), and In-situ Gas Chromatography (GC)
AU: * Bouvier-Brown, N C
EM: nbouvier@nature.berkeley.edu
AF: Department of Environmental Science, Policy, and Management, University of California, Berkeley, 137 Mulford Hall #3114, Berkeley, CA 94720-3114 United States
AU: Holzinger, R
EM: holzing@nature.berkeley.edu
AF: Department of Environmental Science, Policy, and Management, University of California, Berkeley, 137 Mulford Hall #3114, Berkeley, CA 94720-3114 United States
AU: Palitzsch, K
EM: kat_in_india@yahoo.com
AF: TU Bergakademie Freiberg, Interdisziplinaeres Oekologisches Zentrum, Brennhausgasse 14, Freiberg, 09599 Germany
AU: Goldstein, A H
EM: ahg@nature.berkeley.edu
AF: Department of Environmental Science, Policy, and Management, University of California, Berkeley, 137 Mulford Hall #3114, Berkeley, CA 94720-3114 United States
AB: Chemical ozone loss due to reactions with biogenic VOCs has been shown to dominate ozone flux measured at Blodgett Forest, a coniferous forest in the Sierra Nevada Mountains of California. Here we report recent efforts to measure the specific biogenic VOCs involved in this chemistry at Blodgett Forest. During summer 2005, we enclosed branches of Ponderosa pine, manzanita, and ceanothus species and made VOC emission measurements by proton transfer reaction mass spectrometry (PTR-MS), solid phase microextraction (SPME) on fibers followed by direct injection into a gas chromatograph with an ion trap mass spectrometer (GC-ITMS), and by in-situ GC with a flame ionization detector (GC-FID). Zero air, with ambient CO₂ concentrations, flowed through a 2-chamber system. The chamber placed directly over the branch had a 20 second residence time, and was immediately followed by a reaction chamber with a 2 minute residence time. The PTR-MS and GC-FID measurement cycled between each of the two chambers and the zero air supply. SPME fibers (65 μm PDMS/DVB field portable) were used to sample the branch chamber. Several sesquiterpene, monoterpene, and oxygenated primary emissions were identified. The SPME fibers were particularly useful for detecting sesquiterpenes which are typically difficult to measure due to their high reactivity in the forest canopy and losses in sampling lines. Comparisons of SPME fiber data with PTR-MS and GC-FID data for sesquiterpenes (m/z 205), 4-allylanisole (m/z 149), and monoterpenes (m/z 137) will be presented to assess the actual emission rates and the complimentary information provided by each measurement approach.
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005