Abstract
A vacuum distillation method, using carbon dioxide as a transport medium, was applied to tobacco and compared with a charcoal trapping technique with the ultimate aim of studying the alterations of tobacco volatiles during curing and ageing. Examination by gas chromatography in combination with mass spectrometry of the four samples obtained after concentration in three stages showed that they were qualitatively similar, especially with respect to the more abundant constituents. The relative concentration of certain more volatile substances was, however, higher in the case of charcoal trapping, primarily because water-soluble components were not completely recoverable after carbon dioxide distillation. Evaluation of each method at two temperature levels showed that the yields increased markedly with temperature, mainly arising from unproportionally large increases in the concentrations of the major components, nicotine and neophytadiene. Thus, precise operation temperature controI is required, especially in terms of reproducibility. The total yield for the carbon dioxide distillation procedure (85°C) was greater than that for the charcoal trapping (40°C), due to the higher yields of both nicotine and neophytadiene in the former case. Notably because of the greater ease with which the method could be scaled up to allow trace component studies, charcoal trapping at 40°C was accepted as the method of choice for further work.