Chiral ionic liquids as chiral selectors for separation of tryptophan enantiomers by ligand exchange chromatography
来源期刊：中南大学学报(英文版)2013年第5期
论文作者：YANG Yan-xia(杨艳霞) 李静 JIANG Xin-yu(蒋新宇)
文章页码：1173 - 1177
Key words：chiral ionic liquids; chiral separation; ligand exchange chromatography; tryptophan enantiomers
Abstract: Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Several factors influencing Trp enantiomers separation, such as alkyl chain length of CILs, concentrations of Cu2+ and CILs, pH of the mobile phase, flow rate, organic solvent and temperature, were studied. Under the optimal conditions, the Trp enantiomers could be successfully separated within 21 min with the resolution of 2.30. At the same time, some thermodynamical parameters were obtained. The experimental results show that the enthalpy values of the Trp enantiomers are negative, indicating that the separation process is exothermic. And the enthalpy values of D-Trp are larger than those of L-Trp, which indicates that L-Trp could form more stable ternary complexes with tryptophan enantiomers.
YANG Yan-xia(杨艳霞), LI Jing(李静), JIANG Xin-yu(蒋新宇)
(School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China)
Abstract:Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Several factors influencing Trp enantiomers separation, such as alkyl chain length of CILs, concentrations of Cu2+ and CILs, pH of the mobile phase, flow rate, organic solvent and temperature, were studied. Under the optimal conditions, the Trp enantiomers could be successfully separated within 21 min with the resolution of 2.30. At the same time, some thermodynamical parameters were obtained. The experimental results show that the enthalpy values of the Trp enantiomers are negative, indicating that the separation process is exothermic. And the enthalpy values of D-Trp are larger than those of L-Trp, which indicates that L-Trp could form more stable ternary complexes with tryptophan enantiomers.
Key words:chiral ionic liquids; chiral separation; ligand exchange chromatography; tryptophan enantiomers
