Recent advances in the enantioseparation promoted by ionic liquids and their resolution mechanisms

Yohannes, Alula; Yao, Shun

doi:10.1016/j.chroma.2020.461384

Cited by 23 publications

(9 citation statements)

References 175 publications

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“…Either the cation or the anion must be chiral to consider as CILs [ 28 , 59 ]. Recently, Nie et al [ 60 ] reviewed and categorized ILs for enantioseparation and explored their resolution mechanism. Amino acid-based ILs have been proposed for potential use as sole CSs in CEKC [ 61 ].…”

Section: Chiral Capillary Electrokinetic Chromatography Principle and Selectorsmentioning

confidence: 99%

Chiral Capillary Electrokinetic Chromatography: Principle and Applications, Detection and Identification, Design of Experiment, and Exploration of Chiral Recognition Using Molecular Modeling

et al. 2021

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This work reviews the literature of chiral capillary electrokinetic chromatography from January 2016 to March 2021. This is done to explore the state-of-the-art approach and recent developments carried out in this field. The separation principle of the technique is described and supported with simple graphical illustrations, showing migration under normal and reversed polarity modes of the separation voltage. The most relevant applications of the technique for enantioseparation of drugs and other enantiomeric molecules in different fields using chiral selectors in single, dual, or multiple systems are highlighted. Measures to improve the detection sensitivity of chiral capillary electrokinetic chromatography with UV detector are discussed, and the alternative aspects are explored, besides special emphases to hyphenation compatibility to mass spectrometry. Partial filling and counter migration techniques are described. Indirect identification of the separated enantiomers and the determination of enantiomeric migration order are mentioned. The application of Quality by Design principles to facilitate method development, optimization, and validation is presented. The elucidation and explanation of chiral recognition in molecular bases are discussed with special focus on the role of molecular modeling.

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Section: Chiral Capillary Electrokinetic Chromatography Principle and Selectorsmentioning

confidence: 99%

Chiral Capillary Electrokinetic Chromatography: Principle and Applications, Detection and Identification, Design of Experiment, and Exploration of Chiral Recognition Using Molecular Modeling

et al. 2021

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“…However, the high viscosity of sole CILs as solvents should be overcome . Chiral nature substances or their derivatives from chiral pools are superior choices to prepare CILs. , Currently, CILs have been gaining attention in chiral separations in high-performance liquid chromatography (HPLC), liquid–liquid extraction (LLE), and so forth. − Thereby, the anticipated chiral recognition ability of CILs to enhance the resolution has been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Direct Crystallization Resolution of Racemates Mediated in Chiral Ionic Liquid Cosolvent Mixtures: Experimental, Statistical, and QM Simulation Studies

Qin

Lou

et al. 2023

Crystal Growth & Design

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Four chiral ionic liquids (CILs) of 1-hexyl-3-methylimidazolium-l-2-aminobutyrate ([Hmim][l-2-AbA]), 1-hexyl-3-methylimidazolium-d-2-aminobutyrate ([Hmim][d-2-AbA]), di-1-hexyl-3-methylimidazolium-l-malate ([Hmim]2[l-MA]), and di-1-hexyl-3-methylimidazolium-d-malate ([Hmim]2[d-MA]) were first prepared by a neutralization method and adequately characterized. In light of a gravimetric method, the molar fraction solubilities of dl- and d- together with l-threonine (Thr) were then acquired in the binary cosolvent mixtures (CM) of CILs and water, with different mass fractions (ω) of CILs under 101.3 kPa from 283.15 to 333.15 K. In CIL cosolvent mixtures (CCM), a cosolvency phenomenon was observed with the biggest solubilization and discrepant solubilities of Thr enantiomers, with ω of 0.3. Meanwhile, the asymmetry phenomenon was also found from the ternary phase diagram of Thr enantiomers and CCM, in which the enantiomeric excess values at the eutectic point (eeeut) were sensitive to temperature. Subsequently, the nucleation experiments and appearance probability statistics confirmed that CCM with ω of 0.3 (CCM-0.3) can act as excellent nucleation inhibitors which preferred to suppress the nucleation of enantiomeric crystals with the opposite chirality to them, leading to the preferential nucleation of enantiomeric crystals with the same chirality. Furthermore, by coupling seeds and CCM-0.3, the yield and yield ratio of l-Thr products through a direct antisolvent crystallization resolution were improved greatly compared with that in water, where the largest yield ratio was up to 27.47%. At the same time, isosurface diagrams and binding energy calculations by quantum mechanics (QM) revealed that the higher chiral recognition ability of [Hmim]2[l-MA] than [Hmim][l-2-AbA] stemmed from the stronger weak interactions. Particularly, the enhanced direct crystallization resolution can be feasibly recycled owing to the stability and recyclability of the CILs.

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“…In fact, the CSPs of GC based on ILs are more likely to be commercialized than those used in liquid chromatography. This made it possible to guide the synthesis and application of ILs as the stationary phase for GC enantioseparation [58] …”

Section: Introductionmentioning

confidence: 99%

“…This made it possible to guide the synthesis and application of ILs as the stationary phase for GC enantioseparation. [58] Based on above considerations, in this work, a new class of amino acid imidazole ILs IL-3 and IL-4, (Scheme 1), which are easy to functionalize, have excellent stability, negligible vapor pressure, high viscosity, and have good solubility in common organic solvents, suitable for the study of GC stationary phase, was synthesized and used as stationary phase for capillary GC separations. 1 H NMR, MS were used to characterize [28] the IL-3, IL-4 composition and structure.…”

Section: Introductionmentioning

confidence: 99%

The Preparation of Novel Amino Acid Imidazole Ionic Liquids and Their Application as Stationary Phase for Capillary Gas Chromatographic Separations

Zhang

et al. 2023

ChemistrySelect

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In this paper, two new amino acid imidazole ionic liquids IL‐3 and IL‐4 were synthesized for the first time, and their separation performance as the stationary phase for capillary gas chromatography (GC) was tested. The statically coated IL‐3 and IL‐4 capillary columns exhibited moderate to high polarity, and achieved the column efficiency of 2242 plates/m and 2487 plates/m respectively determined by n‐octanol at 120 °C. Importantly, the IL‐3 and IL‐4 columns exhibited excellent separation capability for analytes with varying polarity, including n‐alkanes, arenes, esters, alcohols, bromoalkanes, halogenobenzenes, and halogenated anilines. In addition, the IL‐3 and IL‐4 columns presented high selectivity and separation capability for positional, structural and cis‐/trans‐isomers. In particular, they showed high separation performance of the chloroaniline, bromaniline, iodoaniline and xylidine isomers as an important environmental pollutant. The IL‐3 and IL‐4 columns displayed advantageous resolving capability over the commercial HP‐35 column for aromatic amine isomers, and the separation performance of IL‐4 with long carbon chain was better than that of IL‐3. Moreover, it was applied to determine isomer impurities in real samples, and showing huge potential in GC applications. This work demonstrates the potential of the amino acid imidazole ionic liquids as a new type of stationary phase in GC separations.

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Recent advances in the enantioseparation promoted by ionic liquids and their resolution mechanisms

Cited by 23 publications

References 175 publications

Chiral Capillary Electrokinetic Chromatography: Principle and Applications, Detection and Identification, Design of Experiment, and Exploration of Chiral Recognition Using Molecular Modeling

Chiral Capillary Electrokinetic Chromatography: Principle and Applications, Detection and Identification, Design of Experiment, and Exploration of Chiral Recognition Using Molecular Modeling

Enhanced Direct Crystallization Resolution of Racemates Mediated in Chiral Ionic Liquid Cosolvent Mixtures: Experimental, Statistical, and QM Simulation Studies

The Preparation of Novel Amino Acid Imidazole Ionic Liquids and Their Application as Stationary Phase for Capillary Gas Chromatographic Separations

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