Tobacco Chemistry. 3: Unsaturated Hydrocarbon Constituents of Greek Tobacco

Tobacco from Serres, Greece, has been studied with respect to the content of unsaturated hydrocarbons. The isolation of these constituents involved as a key step distillation with the aid of a new technique using carbon dioxide as carrier gas and total condensation of this and the distillate at liquid nitrogen temperature. In addition to the main constituent, neophytadiene, the unsaturated hydrocarbon fraction was shown to contain a series of aromatic compounds. These were examined by means of gas chromatography on capillary columns and also by gas chromatography in combination with mass spectrometry. Fractions were examined before and after elimination of smaller amounts of accompanying olefinic material with the aid of osmium tetroxide. The aromatic constituents were found to be alkylated benzene and naphthalene derivatives, of which many have been identified unambiguously. The vast majority of these have not previously been encountered in tobacco. Several have, however, been detected in smoke and the present results therefore show that these compounds are not necessarily formed solely in the pyrolysis process