Evidence for Peroxynitrite and Cognates in Whole Smoke

The peroxynitrite anion (ONOO-), a major product of the gas-phase interaction between the superoxide radical and nitric oxide, has been detected by ion chromatography (IC) for the first time. IC analyses of cigarette whole mainstream smoke collected in deionized water (DiW), using a Dionex 4500i IC, a Dionex AS11 column, an aqueous sodium hydroxide linear gradient with conductivity suppression from 1-20 mMNaOH, and conductivity coupled with diode array detection, revealed an unknown singly charged anion I incompletely resolved from nitrite. Gradient modification produced baseline resolution of I from nitrite and from a number of additional, previously undetected anions associated with smoke samples. Possible candidates for the unexpected smoke sample anion, including bromide, cyanide, and hydrogen hyponitrite were rejected for possible correspondence with the new smoke species on the basis of concentration range and chemical behavior. Chemical, chromatographic, and spectroscopic evidence supported the assignment of this smoke component as ONOO^-. Mineral acid immediately destroyed I in the collected aqueous smoke medium. Both the retention time and the ultraviolet spectrum (UV) maximum at 302 nm for I were identical to those for synthetic peroxynitrite. The smoke from full flavor [28.5-30.4 mg total particulate matter (TPM)] filter cigarettes contained 2.4-3.3 µg/cig of this species. Levels were 4 to 5 times higher, up to 13 µg/cig, in cigarettes with the filters removed.