Prediction of retention times in comprehensive two-dimensional gas chromatography using thermodynamic models
A method was developed to accurately predict both the primary and secondary retention times for a series of alkanes, ketones and alcohols in a flow-modulated GC × GC system. This was accomplished through the use of a three-parameter thermodynamic model where ÎH, ÎS, and ÎCp for an analyte's interaction with the stationary phases in both dimensions are known. Coupling this thermodynamic model with a time summation calculation it was possible to accurately predict both 1tr and 2tr for all analytes. The model was able to predict retention times regardless of the temperature ramp used, with an average error of only 0.64% for 1tr and an average error of only 2.22% for 2tr. The model shows promise for the accurate prediction of retention times in GC × GC for a wide range of compounds and is able to utilize data collected from 1D experiments. âº Thermodynamic prediction of retention time applied to GC × GC separations. âº Under GC × GC conditions, thermodynamic model is superior to retention index in 1D. âº New model offers easy prediction for 2D, unlike retention index which is cumbersome.