In a preliminary project, a method and a device for fast and efficient gas chromatography were developed. This device counterintuitively uses a negative thermal gradient along the separation column to focus the analytes in very narrow zones during the separation. This gradient is moved along the separation column using a column heater that can be heated in segments. This creates a temperature wave (hence “wavemaker”) that carries the analytes towards the detector. While it was already shown in the preliminary project that extremely fast and very efficient separations can be achieved with this system, a comprehensive theoretical description and explanation is still missing, which is necessary for a targeted optimization of the system and thus also for the commercial success of this unit. In particular, it should be clarified whether, for this special form of chromatography, the separation speed, separation efficiency and capacity of the column are interrelated in such a way that they cannot be optimized at the same time.
The usual deterministic models are not suitable for modelling this particular form of chromatographic separation, especially under non-ideal separation conditions. Therefore, in the first part of the project, a numerical simulation model will be developed that takes into account aspects of fluid mechanics, heat transfer and the interaction of the analytes with the stationary phase. The comparison of modelled and experimental data should be used to determine whether or where optimization opportunities exist for the Wavemaker and corresponding improvements to the design can be made. These are intended to make the device attractive in order to enable users of conventional GC to achieve significantly faster (factor 10x) and more efficient separation by using this module.
In the second part of this project, the potential of this device for use in comprehensive two-dimensional gas chromatography (GCxGC) will be investigated. The ability to generate extremely fast temperature gradients also expands the application range of GCxGC, where the volatility of the analytes otherwise limits the separation efficiency in the second dimension and thus the peak capacity of the entire system. By using the wavemaker for temperature-programmed separation in the second dimension, comprehensive two-dimensional gas chromatography can also be used for difficult samples for which it was previously not satisfactorily applicable. The aim of this second part of the project is therefore to adapt the wavemaker so that it can be installed in a GCxGC system and to optimize the operating parameters required for this.
The Wavemaker thus makes a significant contribution to making both one- and comprehensive two-dimensional gas chromatography faster, more efficient and more environmentally friendly.
