| Gas Chromatography is the most widely used method for the separation and identification of complex mixtures of volatile compounds. However, for all but the simplest mixtures there are either too many components to achieve complete separation or the sample dynamic range is too great for complete analysis. In these cases, a different approach to the separation is mandatory. One way of increasing the separation power of GC is through use of multidimensional methods, which can overcome the inherent short-comings of single-stage chromatography. Multidimensional gas chromatography (MDGC) has significant advantages over a single column system, since two or more columns with different stationary phase polarities and temperatures are coupled in such a way that individual peaks or peak groups can be transferred from one column into another for better separation and some of the analytically important chromatographic parameters can be manipulated such as the column inside diameter and length, polarity of the stationary phase, phase ratio of the coupled columns and temperature program for each column. The results of the optimization of these conditions can be an increase in resolution, sensitivity and column lifetime, shorter separation time, and avoidance of column and detector contamination.;All separations discussed here were carried out using a Siemens SiChromat-2 MDGC. In this project three applications were selected to demonstrate the versatility of an appropriately designed MDGC instrument which can be adapted to analyse very diverse sample types. The three projects undertaken were: (1) quantitative and qualitative analysis of conjugated estrogens in a commercially available pharmaceutical preparation, using a single column; (2) use of MDGC to separate and identify target compounds and biomarkers of petroleum accelerants in suspected arson samples; analysis of semivolatile flavor compounds of cinnamon for (3) the determination of the botanical origin of cinnamon by series-coupled column GC. |
