Advantages of Mixed Mode HPLC for Polar Compounds

It was a relief when I used the brand new Cogent UDA™ columns for analysis of closely related polar compounds. I used them in the Aqueous Normal Phase (ANP) retention mode with additional selectivity of the Ion exchange chromatography capacity.
                With the Cogent UDA 2.o™ column, you can have the best of both worlds by using each retention mode together to obtain excellent separations. In the latest study from our laboratories, we demonstrated the ion exchange characteristics of the Cogent UDA 2.o™ column by separations of three test solutes. With a carboxylic acid group at one of the bonded ligand, ion exchange propertied can be either activated or inactivated by selection of the mobile phase pH.  Under acidic conditions, the carboxylic acid is protonated and neutral and no ion exchange occurs. At mild pH, the group becomes de-protonated and anionic. When the group was ionized, increased retention and separation of the three basic test analytes were observed.

                You can read about the full investigation here.

Separation of the three analytes under ion exchange conditions