Comprehensive two-dimensional GC of supercritical fluid and pressurized liquid extracts of tobaccos.

The developments of an analytical strategy based on rapid extraction techniques coupled to comprehensive bi-dimensional gas chromatography (GCxGC) for the characterization of the volatile fraction of tobaccos are presented. The high-peak capacity of GCxGC allows considering global extraction techniques that do not focus on restricted chemical families of products. Thus, potential of pressurized fluid extraction and supercritical fluid extraction (SFE) to provide informative extracts is evaluated and compared. As expected, both techniques enable rapid extraction of compounds of interest. However, because of the easy removal of the extracting fluid, SFE provides more concentrated extracts, allowing a GCxGC direct injection without any concentration step. Moreover, the use of pure carbon dioxide with tuneable extraction power favors the extraction of the compounds of interest while reducing the extraction of interfering heavy compounds. GCxGC conditions, especially concerning the set of columns used, are selected thanks to the comparison of separations obtained on model compounds. The developed methodology is applied not only to compare the three main types of tobaccos but also to discriminate between different tobaccos of the same type.

Determination of small phosphorus-containing compounds by capillary electrophoresis.

The review focuses on the analysis of small phosphorus-containing compounds by capillary electrophoresis (CE) with different detection modes including UV absorption, laser-induced fluorescence, conductometry, amperometry, atomic spectrometry, and mass spectrometry. Determinations of phosphates, organophosphate, and chemical warfare agents in environmental samples such as water, soil and grains are emphasized. To achieve better sensitivity, high-resolving power, and reproducibility, the optimum separation conditions for various analytes (samples) are different. We compare the merits and demerits of the different detection modes for the detection of the analytes. Although the present methods are successful in many cases, there is still a need to develop high-throughput CE techniques for screening numerous environmental samples and sample stacking techniques in CE for the analysis of trace analytes.