Detection of Free Radicals From the Reactions of Ozone With Olefins and From Cigarette Smoke by Electron Spin Resonance Techniques.

A novel technique is presented that allows detection of free radicals from ozone-olefin reactions for the first time. Olefins are ozonated at -78(DEGREES)C, the unreacted ozone removed, the spin trap added, and the solution warmed. The radicals spin trapped indicate that trioxygenated intermediates are produced that decompose to radicals on warming. Ozonation of cyclic acetals by this procedure yields acyl hydrotrioxides that decompose on warming to produce hydroperoxyl radicals, HOO(.). Alkoxyl radicals are spin trapped when mainstream cigarette smoke is bubbled through PBN solutions while acyloxyl radicals are spin trapped friom sidestream smoke. Stable radicals detected in cigarette tar are found by a combination of fractionation and ESR to be similar to the animal pigment, melanin