Predictions of comprehensive two-dimensional gas chromatography separations from isothermal data

Area of Science:

• Analytical Chemistry
• Chromatography

Background:

• Comprehensive two-dimensional gas chromatography (GC×GC) is a powerful separation technique.
• Accurate prediction of retention times and peak widths is crucial for method optimization and compound identification.

Purpose of the Study:

• To develop and validate a theoretical model for predicting two-dimensional retention times and peak widths in temperature-programmed GC×GC.
• To assess the model's accuracy using experimental data from n-alkanes and polyaromatic hydrocarbons (PAHs).

Main Methods:

• A theoretical model was developed using experimental data from isothermal conditions.
• A Matlab program was created to calculate key chromatographic parameters: dead time (tM), elution temperature (Te), retention time (tR), hold-up width (wM), and peak width (wR).
• The model's predictions were compared against experimentally determined values for a mixture of n-alkanes and PAHs.

Main Results:

• Predicted two-dimensional retention times showed excellent agreement with experimental values.
• Relative deviations were less than 2% for primary and 7% for secondary retention times.
• Relative deviations for peak widths were under 7% (primary) and 10% (secondary).

Conclusions:

• The developed theoretical model provides a simple and effective method for predicting GC×GC parameters without relying on theoretical constants.
• This model is valuable for optimizing GC×GC separation conditions and aiding in the identification of complex mixtures.
• The model's accuracy supports its utility in confirming compound identifications, especially for co-eluting peaks with similar mass spectra.