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E. Papaefstratiou, N. Thomaidis, E. Rosenberg:
"A Comparison of the Quantitative Detection Abilities of One- and Comprehensive 2D-GC and a Proposal for the Definition of the LOD in Comprehensive 2D-GC";
Poster: 19th International Symposium on Separation Science, Porec, Croatia; 2013-09-25 - 2013-09-28.

Although comprehensive two-dimensional gas chromatography (2D-GC) has been in use now for more than 20 years, it is still mostly seen as a qualitative technique, allowing the separation of complex mixtures with a resolving power unparalleled by even the most advanced one-dimensional separations.
In this presentation we concentrate, however, on the quantitative aspects of this technique which, similar to its qualitative separation capabilities, are highly favourable: In theory, comprehensive 2D-GC offers improved detection limits over the one-dimensional technique, as there is a re-focusing of the analytes before their transfer to the 2nd dimension column, leading to very narrow and proportionally higher peaks. On the other hand, a single 1st dimension peak is usually split, as an effect of the applied modulation, into two or more 2nd dimension peaks which reduces sensitivity again. Although it is clear that the quantitation ability of comprehensive 2D-GC will to a great extent depend on the modulation parameters, this topic has only recently been the subject of more detailed investigations [1,2]. Before that, the common understanding was that the quantitative response of 2D-GC should be the same as for 1D-GC, following the principle that "what goes in must come out" [3].
We demonstrate in this presentation that this latter assumption is an over-simplification of the actual situation. Experimental conditions are likely to introduce a bias to the determination of concentrations in the comprehensive 2D-GC chromatogram when using 1D-GC data for calibration. This was demonstrated by using a set of alkylbenzene standards which were analysed under different modulation conditions. The experimental derived LODs did not reflect the enhancement in peak height resulting from the modulation. This led us to propose a new model for the determination of LODs (and LOQs) from modulated signals resulting from comprehensive 2D gas chromatograms, which is presented and discussed in detail.

References
[1] A.P. de la Mata, K.D. Nizio, J.J. Harynuk, J. Chromatogr. A, 1255 (2012) 190-195.
[2] J. Krupčík P. Májek, R. Gorovenko, I. Spánik, P. Sandra, D.W. Armstrong, J. Chromatogr. A 1286 (2013) 235-240.
[3] M. Kallio, T. Hyötyläinen, J. Chromatogr. A, 1148 (2007) 228-235.