Properties of reversed phase packings with an embedded polar group

Reversed-phase packings with an incorporated polar group, specifically a ca rbamate group, are compared with classical packings and the results are dis cussed. In this study, the underlying silica and the surface coverage are i dentical, allowing for a simple and unequivocal comparison of the sorbent p roperties that originate solely in the nature of the ligand. The polar grou p contributes to improved peak shapes for acidic, basic and zwitterionic an alytes and changes the selectivity of a separation compared to classical bo nded phases. A chromatographic technique that allows a discrimination betwe en classical bonded phases and those with an incorporated polar group is de scribed. In addition, phases with an embedded polar group can be used witho ut difficulty in mobile phases with a very high water content, which makes them suitable for the separation of very polar analytes.