¹D‑Guided Differential Rescaling of a Contour Plot in Comprehensive 2D Gas Chromatography

A ¹D-guided differential rescaling algorithm for a contour plot is developed based on our recently proposed comprehensive two-dimensional gas chromatography (GC × GC) system with a first-dimensional (¹D) detector added. Chromatograms obtained from ¹D and second-dimensional (²D) detectors are both incorporated during the data processing. As compared to the conventional contour plot methods using only ²D data, our algorithm can significantly improve precision and consistency of GC × GC results in terms of retention times, peak widths, and peak areas or volumes, regardless of modulation time selection, modulation phase shift fluctuations, and modulation duty cycle. The peak identification, quantification, and capacity can therefore be enhanced. Furthermore, the ¹D-guided differential rescaling method is shown to better handle the coelution and missing peak issues often encountered in the conventional methods. Finally, the new method exhibits high versatility in ¹D and ²D detector selection, which greatly broadens GC × GC utility. Our method can easily be adapted to other two-dimensional chromatography systems that have direct access to ¹D chromatograms.