Classical Multidimensional Gas Chromatography

In order to expand the analytical separation, chromatographers have developed a range of solutions based on more than one separation space. Termed MDGC, it consists of an arrangement of two or more columns where distinctive segments of effluent from the first column are fed into one or more secondary columns (Fig. 15.1). 

The entire procedure is enabled by the presence of a specific transfer device between the two columns. Cortes [10] and Bertsch [11, 12] have presented a comprehensive discussion of conventional MDGC technology and their contributions are recommended to readers who wish to have a more detailed outline of MDGC and its applications. 

The mechanism by which effluent is switched from the first to the second column is critical. Column flows are diverted basically by using valves or valve- 

Apart from petrochemical and environmental applications [12], classical MDGC was/is used in the flavour field mainly for enrichment and identification of odorous trace compounds in complex mixtures, or for authenticity evaluation by chiral separation or isotopic ratio determination. In Table 15.1 some typical applications are given. 

In order to illustrate the potential of MDGC when dealing with complex mixtures, an application to determine off-flavour compounds in defective coffee beans is given byway of example (Fig. 15.3) 

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