HR: 1340h
AN: A33D-1564    [Abstracts]
TI: Ozonolysis of Unsaturated Phosphocholines on NaCl as a Model for Organics on Sea Salt Particles
AU: * Karagulian, F
EM: fkaragul@uci.edu
AF: University of California Irvine, University of California Irvine, Department of Chemistry, Irvine, CA 92697, United States
AU: Lea, A
EM: scott.lea@pnl.gov
AF: Pacific Northwest National Laboratory, W.R.Wiley Environmental Science Laboratory, Richland, WA 99352, United States
AU: Finlayson-Pitts, B
EM: bjfinlay@uci.edu
AF: University of California Irvine, University of California Irvine, Department of Chemistry, Irvine, CA 92697, United States
AB: Sea salt particles, which are a major contributor to the global aerosol burden, may be coated with organic material. A major source of organic material is the decomposition of marine organisms, which have biomembranes that are a mixture of lipids, hydrophobic proteins and carbohydrates. The ozonolysis of 1-oleoyl- 2-palmitoyl-sn-glycero-3-phosphocholine (OPPC) on NaCl as a model for this organic coating on sea salt was followed in real time using diffuse reflectance infrared Fourier transform spectrometry (DRIFTS). Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry and Auger electron spectroscopy were used to confirm the identification of the products. Upon exposure to O3, we observed a stable secondary ozonide (SOZ) as well as carbonyl-containing products. The kinetics of formation of these products and the impact of water vapor and photolysis on them were studied. Water vapor decreased the SOZ yield, and photolysis in the actinic region led to loss of the SOZ and the generation of aldehydes, carboxylic acids and anhydrides. These experiments elucidate the mechanism of formation of secondary ozonides on surfaces in polluted and relatively dry environments, which should be taken into account in the chemistry, photochemistry and toxicity of coastal atmospheres and those in the vicinity of dry, alkaline lakes.
DE: 1050 Marine geochemistry (4835, 4845, 4850)
DE: 4850 Marine organic chemistry (0470, 1050)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting