Assessment of tobacco-specific N-nitrosamines in tobacco products.

Abstract

Tobacco-specific nonvolatile N -nitrosamines in tobacco and in fresh mainstream and sidestream smoke of cigarettes and cigars were quantitatively determined with a thermal energy analyzer. The smoke was trapped in ascorbic acid solution buffered at pH 4.5 and extracted with dichloromethane, and the organic phase was chromatographed and analyzed by high-performance liquid chromatography-thermal energy analyzer methodology (sensitivity, 250 pg/injection). The nonvolatile nitrosamines were further enriched by repeated chromatography and positively identified by gas-liquid chromatography-mass spectrometry. [2′-14C] N ′-nitrosonornicotine served as internal standard for the quantitative analysis. The tobacco of five different cigarettes contained between 0.22 and 7.0 ppm of the carcinogenic N ′-nitrosonornicotine, 0.13 and 0.74 ppm of the carcinogenic 4-( N -methyl- N -nitrosamino)-1-(3-pyridyl)-1-butanone, and 0.44 to 3.2 ppm of the newly identified N ′-nitrosoanatabine. In unaged mainstream and sidestream smoke of the same cigarettes, values ranged between 0.24 and 3.7 and 0.15 and 6.1 µg/cigarette for N ′-nitrosonornicotine, between 0.11 and 0.42 and 0.19 and 0.66 µg/cigarette for 4-( N -methyl- N -nitrosamino)-1-(3-pyridyl)-1-butanone, and between 0.33 and 4.6 and 0.15 and 1.5 µg/cigarette for N ′-nitrosoanatabine, respectively. The relatively high concentrations of these carcinogenic N -nitrosamines in sidestream smoke are discussed as possible tobacco-specific indicators for indoor pollution.