HR: 1330h
AN: C42A-1016    [PDF]
TI: Photolysis of Nitrate and Nitrite in Artificial Snow and Artificial Ice
AU: * Shi, W
EM: weshi@mtu.edu
AF: Chemistry Department. Michigan Technological University, 1400 Townsend Drive, Houghton, MI 499131 United States
AU: Green, S A
EM: sgreen@mtu.edu
AF: Chemistry Department. Michigan Technological University, 1400 Townsend Drive, Houghton, MI 499131 United States
AB: It is well known that nitrate and nitrite undergo photolysis in aqueous solution. Recent studies show that these reactions are likely to occur in natural snow as well. Therefore it is of interest to measure rates of photolysis of nitrate and nitrite in snow and ice. In this study artificial snow was made by spraying a solution onto the wall of a reservoir containing liquid nitrogen. Artificial snow and ice were irradiated in a sealed quartz tube with a UV lamp and production of hydroxyl radicals was quantified. Hydroxyl radicals produced in these processes react with dimethyl sulfoxide to release methyl radicals, which were trapped by 3-amino-2,2,5,5-tetramethyl-1-pyrrolidinyloxy free radical (3AP). The 3AP-CH$_{3}$ compound was later derivatized to produce a highly fluorescent adduct, which was measured by HPLC. Snow produced the highest yield of hydroxyl radicals and ice the lowest. Nitrite had higher yield than nitrate. The calculation of photolysis rates for nitrate and nitrite in snow and ice is discussed.
DE: 0317 Chemical kinetic and photochemical properties
DE: 0322 Constituent sources and sinks
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2003 Fall Meeting