色谱 ›› 2020, Vol. 38 ›› Issue (9): 1028-1037.DOI: 10.3724/SP.J.1123.2020.02010

• 专论与综述 • 上一篇    下一篇

毛细管电泳新型手性分离体系研究进展

张琪()   

  1. 江苏大学药学院, 江苏 镇江 212013
  • 收稿日期:2020-02-17 出版日期:2020-09-08 发布日期:2020-12-11
  • 通讯作者: 张琪
  • 作者简介:张琪.Tel:(0511)85038451, E-mail:zhangqi@ujs.edu.cn
  • 基金资助:
    国家自然科学基金(81703465);江苏省自然科学基金(BK20170533)

Recent advance of novel chiral separation systems in capillary electrophoresis

ZHANG Qi()   

  1. School of Pharmacy, Jiangsu University, Zhenjiang 212013, China
  • Received:2020-02-17 Online:2020-09-08 Published:2020-12-11
  • Contact: ZHANG Qi
  • Supported by:
    National Natural Science Foundation of China(81703465);Natural Science Foundation of Jiangsu Province(BK20170533)

摘要:

在现代分离科学中,手性化合物的分离分析一直是研究的重点和难点。相比于高效液相色谱(HPLC)、气相色谱(GC)等传统色谱分析方法,毛细管电泳(CE)技术凭借其高效率、低消耗、分离模式多样化等诸多优势,已经发展成为手性分离研究领域最有应用前景的分析方法之一。近年来,研究人员在CE手性分析方法的构建过程中,基于毛细管电动色谱(EKC)、配体交换毛细管电泳(LECE)、毛细管电色谱(CEC)等各种基础电泳模式,不断地对传统手性分离体系进行优化和改造,构建出了许多高性能的新型手性CE分离体系。如利用各类功能化离子液体以"手性离子液体协同拆分""手性离子液体配体交换""离子液体手性选择剂"等模式设计出多种基于离子液体的CE手性分离体系;利用纳米材料独特的尺寸效应、多样性、可设计性等特点,直接或与传统手性选择剂有机结合构建CE手性分离体系。此外,金属有机骨架材料修饰、低共熔溶剂修饰、非连续分段式部分填充等各式新颖的CE手性分离体系也都被研究人员成功开发,并表现出较大的发展潜力。该综述将对近年来(尤其是2015~2019年)此类新型CE手性分离体系的发展状况进行梳理,并结合相应的手性识别机理研究和手性CE方法实际应用情况,对该领域存在的问题及发展前景进行分析和展望。

关键词: 毛细管电泳, 手性分离, 离子液体, 纳米材料, 金属有机骨架, 低共熔溶剂, 机理, 综述

Abstract:

Chiral analysis has been an important research field in modern separation science because the enantiomers of a racemic compound often show different or even opposite bioactivities. A variety of analytical techniques have been adopted for chiral analysis over the past few decades. In comparison with conventional chromatographic methods (e. g., high-performance liquid chromatography (HPLC), gas chromatography (GC)), capillary electrophoresis (CE) has multiple advantages such as high separation efficiency, low cost, and diverse separation modes, which have made it one of the most promising analytical techniques for enantioseparation in recent years. The simplest process for CE chiral separation is the addition of a chiral selector (e. g., cyclodextrins and their derivatives, polysaccharides, antibiotics, proteins, crown ethers, chiral exchangers, chiral ionic liquids) in a running buffer to create a chiral separation environment. However, with the ever-increasing number of chiral products in the modern industrial society, satisfactory enantioseparation cannot always be achieved with conventional CE methods. Hence, scientists are endeavoring to improve CE chiral methods. The availability of various fundamental operational modes such as capillary zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC), ligand-exchange capillary electrophoresis (LECE), non-aqueous capillary electrophoresis (NACE), and capillary electrochromatography (CEC) has enabled researchers to realize flexible design of high-performance CE chiral separation systems by altering the CE operations, especially by the modification of various advanced materials. For example, ionic liquids (ILs) are a group of organic salts whose melting points are below 100℃, or more often, close to room temperature. ILs have been demonstrated to be effective modifiers in chiral CE because of their unique physical and chemical properties such as high conductivity, exceptional chemical and thermal stabilities, as well as excellent solubility in both organic and inorganic solvents. Besides, it is feasible to design and synthesize various task-specific ILs by altering their anion-cation combinations. ILs have been employed for CE enantioseparation through various modes such as achiral IL-modified conventional enantioseparation systems, chiral IL synergistic separation systems, chiral IL LECE systems, and IL-based MEKC, or by the development of novel IL chiral selectors. Nanoparticles are another class of materials that have received considerable interest for use in chiral CE. Nanoparticles have many advantages such as unique size effect, good chemical stability, significant mechanical strength, as well as ease of modification. Several studies have demonstrated that the combination of chiral selectors with nanomaterials such as gold nanoparticles, Fe3O4 magnetic nanoparticles, carbon nanotubes, and mesoporous silica nanomaterials is a promising approach to establish an EKC system or a CEC system. In this review, we summarize the current state-of-the-art of novel CE chiral separation systems, including enantioseparation systems based on achiral or chiral ILs, nanomaterials, metal-organic frameworks (MOFs), and deep eutectic solvents, as well as chiral plug-plug partial filling CE. Another important topic of research in chiral CE is the exploration of enantiorecognition mechanisms. Modern mechanistic studies focus on the applications of advanced analytical techniques such as nuclear magnetic resonance (NMR) or molecular simulations with computer technology, instead of the conventional chromatography- or CE-based thermodynamic methods. For example, nuclear Overhauser effect spectroscopy (NOESY) and rotating-frame Overhauser enhancement spectroscopy (ROESY) have attracted attention because they provide critical information about the spatial proximity of the functional groups of chiral selectors and enantiomers. Molecular simulations have also become popular because of their powerful ability to evaluate the selector-selectand interactions, in addition to enabling visualization of the complex structures. The main objective of this paper is to provide a comprehensive review of state-of-the art of CE techniques in the field of chiral analysis, especially during the period 2015-2019. Existing problems with these techniques and future perspectives are also presented.

Key words: capillary electrophoresis (CE), chiral separation, ionic liquid, nano material, metal organic framework (MOF), deep eutectic solvent, mechanism, review