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Thursday, April 17, 2014

Organic Matter in Snow and Ice: Characterization and Chemistry

Analytical Chemistry Analytical Seminar
1640 Chemistry
4:00 PM - 5:30 PM

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Speaker:   Amanda Grannas, Villanova University
Abstract:   It is well established that ice is a reactive medium in the environment and that active photochemistry occurs in frozen systems. Snow and ice contain a number of absorbing species including nitrate, nitrite, peroxide, and organic matter. These generate a variety of reactive intermediates upon radiation, such as hydroxyl radical and singlet oxygen. Dissolved organic matter (DOM) is a ubiquitous component of snow and ice and plays an important role in overall light absorption properties of the sample. Additionally, the reactive intermediates produced by DOM photolysis can further react with contaminants present and alter their fate in the environment or may play a role in generation and emission of volatile species to the overlying atmosphere. Unfortunately, the role of DOM in ice photochemistry has received little attention, and characterizing the nature of DOM is hindered due to its complex and heterogeneous nature. Here we will discuss recent efforts to study the photosensitizing properties of DOM under controlled laboratory conditions as well as advances in the characterization of DOM using advanced analytical techniques such as ultra-high resolution mass spectrometry and NMR.