Macroporous polymer monoliths as second dimension columns in comprehensive two-dimensional gas chromatography: A feasibility study

When the typical column combinations are used, comprehensive two-dimensional gas chromatography (GC × GC) suffers from the impossibility to operate both dimensions at their optimum carrier gas velocities at the same time. This as a result of the flow mismatch caused by the different dimensions of the columns used. The objective of the present study was the development of monolithic second dimension columns which would allow simultaneous optimum-velocity operation. With monolithic GC columns the optimum performance can be obtained at any given flow rate by varying the bed structure and column diameter. Different divinylbenzene-based monolithic columns were prepared and evaluated in terms of permeability and performance. Plate heights of less than 0.18 mm and plate generation rates up to 600 plates/s were achieved. 1D-GC experiments performed on short monolithic columns showed a good resolving power thanks to the elevated retention and the good selectivity. A peak capacity up to 12 peaks per 4–5 s was obtained for low-boiling alkanes, confirming the potential for fast separations. Excellent repeatability in terms of retention times (RSD < 0.5%) and peak widths (RSD < 1.5%) was observed. The columns prepared were successfully used in the second dimension of a GC × GC setup with a standard non-polar first dimension. Model experiments proved the possibility to operate both dimensions at their optimum linear velocity simultaneously. The suitability of the novel second dimension column format to perform multidimensional separations was shown for selected applications.

► Divinylbenzene monoliths as stationary phases for new GC columns.
► Good performance for fast GC separations with a peak capacity of 12 peaks per 5 s.
► New monolithic columns coupled as second dimension for GC × GC.
► Multidimensional separation of low-boiling compounds with good orthogonality.
► Possible to operate both dimensions at the optimum linear velocity simultaneously.