Detection and separation of gas-phase carbon-centered radicals from cigarette smoke and diesel exhaust

Carbon-centered radicals were tapped from gas-phase cigarette smoke and diesel engine exhaust hy reaction with a nitroxide, 3-amino-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (3AP). The resulting mixture of stable, diamagnetic adducts was derivatized with naphthalenedicarboxaldehyde (NDA) to produce highly fluorescent products. Derivatives were separated hy high-performance liquid chromatography (HPLC), which revealed distinctly different suites of radicals present in the two systems. Integration of HPLC peaks gave approximately 22 +/- 7 nmol of radicals per cigarette and 3 +/- 1 nmol of radicals per liter of diesel engine exhaust. An estimated 8-10 different carbon-centered radical species are present in each system.