10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
The Condensed-phase Ozonolysis of an Unsaturated Triglyceride: Reaction Kinetics and Products
ZILIN ZHOU, Shouming Zhou, Jonathan Abbatt, University of Toronto, Canada
Abstract Number: 912 Working Group: Aerosol Chemistry
Abstract Ozone plays an important role in both outdoor and indoor chemistry. It is well known that the gas-phase ozone oxidation of gas-phase alkenes, such as terpenes, leads to the formation of oxidized products, such as carbonyls and Criegee intermediates. However, despite the well-studied gas-phase mechanism, the fate of condensed-phase ozonolysis on surfaces and in aerosol particles is still not fully understood. In this study, a common component seen in most cooking oils, triolein (a triglyceride arising from glycerol and oleic acid) was oxidized by ozone on a surface. The rapid decay of triolein was observed, accompanied by the formation of secondary ozonides and a series of oxygenated compounds (acids and aldehydes). The uptake coefficient of ozone will be reported. To do this work, a sensitive technique using high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC-ESI-MS) was developed for the quantitative analysis of triolein and its oxidized products. In particular, the reactivity of the secondary ozonide products was also studied using this analytical method, under ambient conditions of light and relative humidity (RH). The results indicate that the condensed-phase oxidative chemistry of triglycerides is complex, driven primarily by the resulting Criegee intermediates. The environmental implications for this chemistry will be discussed. In particular, trigylcerides are an important component of cooking organic aerosol, and they will be deposited on indoor surfaces close to where cooking is performed.