Applications of monolithic columns in gas chromatography and supercritical fluid chromatography.

Porous monoliths are well-known stationary phases in high-performance liquid chromatography and capillary electrochromatography. Contrastingly, their use in other types of separation methods such as gas or supercritical fluid chromatography is limited and scarce. In particular, very few studies address the use of monolithic columns in supercritical fluid chromatography. These are limited to silica-based monoliths and will be covered in this review together with an underlying reason for this trend. The application of monoliths in gas chromatography has received much more attention and is well documented in two reviews by Svec and Kurganov published in 2008 and 2013, respectively. The most recent studies, covered in this review, build on the previous findings and on further understanding of the influence of preparation conditions on porous properties and chromatographic performance of poly(styrene-co-divinylbenzene), polymethacrylate, and silica-based monolithic columns while expanding to polymer-based monoliths with incorporated metal organic frameworks and to vinylized hybrid silica monoliths. In addition, the potential application of porous layer open tubular monolithic columns in low-pressure gas chromatography will be addressed.