Synthesis and chromatographic properties of α-Schiff bases (6-imino)-β-cyclodextrin bonded silica for stationary phase of liquid chromatography

Two new chiral stationary phases (CSPs), 6-deoxyisopropylimino-β-cyclodextrin bonded on the silica gel (YBCDs) and heptakis[2,6-o-diamyl-6-deoxyisopropylimino]-β-cyclodextrin bonded on the silica gel (WYBCDs), were prepared. The chromatographic properties of two CSPs (YBCDs and WYBCDs) were tested. Good resolutions for disubstituted benzene isomers were obtained with YBCDs. l- and d-amino acids mixtures were well separated on both YBCDs and WYBCDs. The influence of pH of aqueous triethylammonium acetate buffer (TEAA) was also studied on the two CSPs. Experimental results show that WYBCDs enhances the retention of amino acids. It is proposed that the amylation modification above the cyclodextrin (CD) partially occludes the mouth of the CD cavity and sterically influences the formation of inclusion complexes, leading to the change in solute retention.