Preparation of methylated β-cyclodextrin bonded stationary phases and chromatographic evaluation for chiral separation

A native and two types of methylated beta-cyclodextrin(CD)-bonded stationary phases have been prepared and their ability to separate enantiomers of eight 2,4-dinitrophenyl amino acids was investigated by revered-phase high performance liquid chromatography. When heptakis(3-O-methyl)-beta-CD bonded stationary phase was compared with the native beta-CD stationary phase, increased enantioselectivity and peak resolution were observed for aromatic amino acids. Effects of organic modifier content and pH of the mobile phase on retention and enantioselectivity for the analytes were examined to optimize mobile phase conditions. The elution order of racemates of all analytes on both the native and heptakis(3-O-methyl)-beta-CD bonded stationary phases was D before L enantiomer. The structural features of the analytes on retention, enantioselectivity and peak resolution were examined and discussed.