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E. Rosenberg:
"Complex samples, complex methods - Application of two-dimensional chromatography hyphenated to mass spectrometric detection in food and environmental analysis";
Hauptvortrag: IMA 2013 - Instrumental Methods of Analysis, Thessaloniki, Greece (eingeladen); 15.09.2013 - 19.09.2013.

At trace level, even the simplest seeming sample is of enormous complexity: While a sample can contain only few major constituents, this number increases to perhaps 10-20 for minor constituents, and at trace level hundreds, if not thousands of different compounds may be present.
Conventional separation techniques, i.e., one-dimensional gas and liquid chromato- graphy do, however, not offer the resolution power required to resolve the majority of the compounds present. It can be demonstrated by theoretical considerations [1] that, when run under typical conditions, gas chromatography is capable of resolving some one hundred compounds in one run, while for liquid chromatography this number is even lower. This calls for multi-dimensional separations which have the potential of resolving a significantly higher number of analytes, particularly when operated in the comprehensive two dimensional chromatography mode [2]. In the ideal case, the peak capacity of a comprehensive 2D separation system is the product of the peak capacity of the first and the second dimension column. Even if only a relatively small peak capacity can be obtained for the separation in the second column dimension the peak capacity of the 2D system increases dramatically, making thus possible the separation of samples even of high complexity.
In practice, however, only a fraction of the theoretical 2D peak capacity is actually achievable. This is mainly due to the correlation of the separation mechanisms in gas chromatography, while in liquid chromatography the main reason is the lack of an appropriate refocusing when the analytes are injected into the second separation dimension, and the relatively limited compatibility of mobile phases for stationary phases which are truly orthogonal.
To a certain extent, these limitations can be overcome by optimization of the 2D separation conditions. This presentation will discuss rational approaches to do so in both gas and liquid chromatography. Advantages and shortcomings of the different approaches will be critically discussed, and applications from the environmental field (e.g. pesticides, phenols, industrial chemicals) and from food analysis (e.g. polyphenolic substances, vitamins) will be presented for both, 2D-GC and 2D-LC. Based on this, recommendations for efficient separation in comprehensive 2D-chromatography will be given.

References
[1] J.C. Giddings, Unified Separation Science, Wiley, New York (1991).
[2] L. Mondello, A.C. Lewis, K.D. Bartle, Multidimensional Chromatography. Wiley, New York (2001).