Analysis of the basics and modelling of the Flow-Field-Thermal-Gradient-Gas-Chromatography

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The aim of the research proposal is the analysis of the basics of a new gas chromatographic (GC) method with a longitudinal negative temperature gradient. With such a gradient the chromatographic bands are permanently focussed because the peak fronts are decelerated and the peak tails are accelerated, respectively. This focussing effect compensates the diffusive band broadening. As the temperature level of the column is enhanced simultaneously the substances on the column are trapped at a distinct temperature that is determined by the equivalence of the chromatographic velocity and the velocity of the temperature along the column. In the gradient field the substances therefore move along the column with a constant temperature without the increase in the classical GC mode. In the context of the previous research program of the applicant and following studies of trace gas analytics a technically simple realisation of the thermal gradient GC has been developed. For the first time it is now possible to study the basics of the thermal gradient gas chromatography (TG-GC) with this experimental setup. The first measurement results are quite promising. With measurement times below 60 s high chromatographic resolutions have been obtained. In contrast to the classical GC up to now only limited experiences and no systematic evaluations of the TG-GC are available. The concept promises a largely improved fast separation which is favourable for e.g. gas sensor systems, ion mobility spectrometry and in combination with mass spectrometry. Due to the reduced separation temperatures also thermally labile components such as some aroma compounds, biological substrates and also energetic materials can be separated and analysed by TG-GC.