Direct equations to retention time calculation and fast simulation approach for simultaneous material selection and experimental design in comprehensive two dimensional gas chromatography

Abstract

Column selection and experimental design are recognized to be wear-and-tear processes to obtain a good fingerprinting result with comprehensive two dimensional gas chromatography (GC × GC). The processes involve a large number of experiments for analysis of each sample due to the optimized conditions depending on the selected column sets. In this study, the analytical solutions of time summation model combined with temperature dependent linear solvation energy relationship (LSER) were derived for constant flow separation in GC × GC. The derived equations allow calculation of analyte retention time in first and second dimensional separation (1tR and 2tR), under temperature program separation employing any column combination with known LSER database. As a result, optimization software was developed enabling simulation of several hundred thousand GC × GC results (fingerprints) for separation of each sample. Good correlations between our predicted results and the results obtained with the previously established numerical approach, were obtained with the R2 of 1.000 and 0.998 for simulation of 1tR and 2tR, respectively. The developed approaches were further applied to simulation of 96,000 individual fingerprints in temperature programmed GC × GC, with the focus on application of 16 column sets including non-ionic liquid and ionic liquid (IL) stationary phases for separation of 678 model compounds. These approaches resulted in the computational time of 1 day compared with 1 year provided by the numerical method. Best column sets and experimental conditions (secondary column lengths and temperature programs) could then be extracted according to maximizing number of separated peaks in separation, which represents the quality of each fingerprinting.