| Comparison of Gas-Phase Free-Radical Populations in Tobacco Smoke and Model Systems by HPLC Thomas M. Flicker and Sarah A. Green Abstract
We used an improved method for trapping carbon-centered radicals ( R) from the gas-phase to compare radical suites trapped from various tobacco smoke and model smoke systems. Using a nitroxide trap, 3-amino-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (3AP) , on solid support, we trapped radicals directly from the gas phase, washed them off the support, and analyzed them with HPLC. Separation of the trapped radicals showed that each tobacco type produced a unique radical suite of 4-10 distinct peaks. Gas mixtures used to model tobacco smoke consisted of nitric oxide, air, isoprene, and methanol. The model systems produced radical suites of four major and several minor peaks, two of which matched peaks in tobacco smoke chromatograms. Quantities of radicals trapped from tobacco smoke were: 54 ± 2 nmol R per Marlboro cigarette, 66 ± 9 nmol R per Djarum clove cigarette, and 185 ± 9 nmol R per Swisher Sweet cigar. In these experiments oxygen competes with the nitroxide trap for gas-phase radicals. A kinetic analysis of the O2 competition shows that actual radical concentrations in the smoke were approximately 100-fold higher than measured. Key words: fluorescence detection, free radical, HPLC, inhaled radicals, isoprene, lung damage, nitroxide, radical detection, smoke reactions, tobacco smoke. Environ Health Perspect 109:765-771 (2001) . [Online 31 July 2001] http://ehpnet1.niehs.nih.gov/docs/2001/109p765-771flicker/ abstract.html Address correspondence to S.A. Green, 1400 Townsend Drive, Department of Chemistry, Michigan Technological University, Houghton, MI 49931. Telephone: (906) 487-3419. Fax: (906) 487-2061. E-mail: sgreen@mtu.edu We thank K. Pregitzer and J. Ashby (Forestry Department, MTU) for HPLC access, and G. McGinnis and M. Manninen (Institute of Wood Research, MTU) for GC/MS assistance. This project was supported by the Graduate School and the Department of Chemistry at MTU, the National Science Foundation #OCE-9712872, and the U.S. Environmental Protection Agency #CR826541-01-1. Received 24 February 2000 ; accepted 30 January 2001.
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