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E. Rosenberg, M. Antoniadou, C. Kanakaki:
"New and Established Approaches to Increase Speed and Throughput in Gas Chromatography";
Hauptvortrag: 11th Chemistry Conference, Plovdiv (eingeladen); 11.10.2018 - 13.10.2018.

NEW AND ESTABLISHED APPROACHES TO INCREASE SPEED AND THROUGHPUT IN GAS CHROMATOGRAPHY
E. Rosenberg, M. Antoniadou and C. Kanakaki1

1 Vienna University of Technology, Institute of Chemical Technologies and Analytics, Getreidemarkt 9/164 AC, A-1060 Vienna, Austria
E-mail: erosen@mail.zserv.tuwien.ac.at

There is a general interest to increase the performance of gas chromatographic methods while maintaining their speed and throughput. According to chromatographic theory, however, the three parameters chromatographic speed, resolution and capacity are mutually exclusive, allowing the optimization of only two of these parameters at one time while compromising the third [1].
A number of approaches have been developed over the last decades to overcome, at least in part, these limitations: These approaches include i) miniaturization of the separation system, ii) the reduction of resolution (for a separation system of traditional dimensions) to a value just sufficient, iii) maximizing the selectivity of the chromatographic system, and iv) implementing a method that reduces analysis time at constant resolution [2]. The three latter approaches are classical optimization approaches. In contrast to this, we have investigated in our group two completely different approaches to increase analysis speed and sample throughput, namely the vacuum outlet or low pressure-GC/MS method and the use of multiplex injection. In the former case, GC separation is performed under conditions which allow maintaining vacuum through the largest part of the GC column. This situation is highly favorable due to the increased diffusion coefficients at reduced pressure, allowing a separation at a much higher linear velocity than under regular pressure conditions [3]. In the latter case, multiplex injection allows the repeated injection of a sample into the GC column before all sample constituents have eluted from the column. The resulting complex chromatogram contains the superimposed information from all individual chromatograms which can be obtained by mathematical deconvolution through the Hadamard transform. This technique can be used both to improve the signal-to-noise ratio of at low analyte concentrations, and to monitor the concentration changes within a sample with high time resolution, governed essentially by the ability to generate short injection pulses [4].
Both approaches will be discussed and compared to other approaches to generate fast chromatographic separations.

Acknowledgements: Financial support of part of this work through the Austrian Research Promotion Agency (FFG) under project nos. 835790 ("SiLithium") and 858298 ("DianaBatt") is gratefully acknowledged.

References
[1] J.V. Hinshaw, LCGC North America, 2017, 35, 810-815.
[2] P. Korytár, H.-G. Janssen, E. Matisová, U.A.Th. Brinkman, Trends Anal. Chem., 2002, 21, 558-572.
[3] C. Kanakaki, PhD thesis, TU Vienna (2018).
[4] M.R. Wunsch, R. Lehnig, O. Trapp, Anal. Chem. 2017, 89, 4038−4045.