Modification of Chiral Stationary Phases with L-Proline as a Selector for Ligand-exchange Chromatography via Introducing Hydrophobic Groups

Three chiral stationary phases(CSP1, CSP2 and CSP3) for ligand-exchange chromatography were prepared by firstly using dimethylchlorosilane as an endcapping reagent for decreasing residual silanol groups on the surface of silica gel, and then modifying the surface of silica gel with allyl glycidyl ether and alkenes through the hydrosilation reaction, and lastly introducing L-proline as a chiral selector. The enantiomer resolutions of 14 amino acids and 2 hydroxyl acids were completed on the CSPs by using an aqueous solution of Cu(Ac)(2) as mobile phase at a flow rate of 1.0 mL/min and column temperature of 40 degrees C with detection at UV 254 run. In terms of enantioselectivity alpha, column efficiency and resolution R-s, the chromatographic behaviors of the analytes on the CSPs were discussed via comparing them to those on the CSP4 prepared via the reference method. The results show that enantioselectivity alpha, column efficiency and resolution R-s of the analytes on the CSPs could be improved by using the above modifying method.