Bull. Spec. CORESTA Congress, Yokohama, 1996, p. 208, S7
Evaluation of fast gas chromatography for the analysis of tobacco components
Philip Morris USA, Research Center, Richmond, VA, USA
Combining experimental skills and novel technologies, gas chromatographic analyses of tobacco can be shortened from 30-60 minutes to several minutes. The dramatic increase in separation speed is achieved with little or no cost in the separation quality. The "fast" approach is not just for time-saving, but also for increasing mass sensitivity and reducing decomposition of labile or active compounds in the GC inlet or during the separation process. Kentucky reference cigarettes - 1R4F were used as samples to optimize experimental parameters for fast GC analysis. Short, narrow bore columns with thin film stationary phase were used to speed up the elution and to minimize the reduction of column efficiency. GC was operated in a constant column flow mode for faster elution of long-retained compounds at lower temperatures. GC profiles of tobacco samples were completed within 1-5 minutes. However, improving detection sensitivity of target compounds by the frequently used splitless injection technique proved to be difficult in fast GC. Sample capacity was limited by the use of small columns and problems associated with evaporation and/or condensation of solvent in the capillary column became more severe. Although the desired sensitivity for the analytes was partially compensated by the increased mass concentration in the narrow peaks produced by rapid elution, other alternative methods were pursued for further improvement. One of the possible ways to minimize the above problems is introducing samples into GC in a solvent-free mode, such as using the newly developed headspace technique - solid phase microextraction (SPME). In SPME, tobacco volatiles were adsorbed on a silica fiber coated with a thin film of polymer and were subsequently desorbed from the fiber in the hot injection port. The above general approaches were applied to the analysis of specific tobacco components, such as alkaloids. The determination of nicotine and several minor alkaloids was achieved in several minutes with resolution and efficiency comparable to that of an established, 30-minute GC procedure. The potential of using fast GC for the determination of other tobacco components also were evaluated.