Eric Lesellier | Authors

Mixed-mode high performance liquid chromatography (MM-HPLC) involves the combined use of two (or more) retention mechanisms in a single chromatographic system. Many original stationary phases have been proposed in recent years with promising possibilities, while applications have only started to appear in the literature. In this review, the authors discuss mixed-mode chromatography stationary phases. An overview of applications using mixed-mode chromatography is described, as well as the increased interest in mixed-mode systems for two-dimensional chromatography.

The carotenoid test allows one to build a simple classification map of stationary phases used in reversed‑phase liquid chromatography, on the basis of the shape recognition (plotted on the x axis), the polar surface activity (plotted on the y axis), and the phase hydrophobicity (related by the bubble size).

The carotenoid test allows one to build a simple classification map of stationary phases used in reversed-phase liquid chromatography, on the basis of the shape recognition(plotted on the x axis) the polar surface activity(plotted on the y axis) and the phase hydrophobicity (related by the bubble size).

Cartenoid compounds can be used as probes for studying the stationary bonded phases devoted for reversed-phase liquid chromatography, that is, C18, phenyl-hexyl, and cholester. From one analysis achieved in supercritical fluid chromatography (SFC) that favors the chromatographic behaviors due to the stationary phase properties, bonding density, ligand type (monomeric or polymeric), and endcapping treatment, two separation factors are calculated allowing us to build a bi-dimentional map. These two axes are related either to the shape selectivity or the polar surface activity (residual silalnos). Each point on the map corresponds to a column. The retention factor of beta-carotene, which describes the phase hydrophobicity, is indicated by the size of the point. More than 200 stationary phases were studied, including small particle sizes and superficially porous ones. Moreover, the results are now available on a website, allowing you to check and compare, by selecting the required tabs, columns, manufacturer brands, and ligand nature.

Cartenoid compounds can be used as probes for studying bonded stationary phases for reversed-phase liquid chromatography, such as C18, phenyl-hexyl, and cholesteryl. From one supercritical fluid chromatography (SFC) analysis that favours the chromatographic behaviours related to the stationary phase properties, bonding density, ligand type (monomeric or polymeric), and endcapping treatment, two separation factors are calculated allowing us to build a two-dimensional map. These two axes are related either to the shape selectivity or the polar surface activity (residual silanols). Each point on the map corresponds to a column. The retention factor of β-carotene, which describes the phase hydrophobicity, is indicated by the size of the point. More than 200 stationary phases were studied, including small particle sizes and superficially porous ones.

The article investigates the ELSD response variation with supercritical carbon dioxide-based mobile phases and compares the response with HPLC.