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Dallocchio R, Dessì A, Sechi B, Peluso P. Molecular Dynamics Simulations of Amylose- and Cellulose-Based Selectors and Related Enantioseparations in Liquid Phase Chromatography. Molecules 2023; 28:7419. [PMID: 37959839 PMCID: PMC10647714 DOI: 10.3390/molecules28217419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
In the last few decades, theoretical and technical advancements in computer facilities and computational techniques have made molecular modeling a useful tool in liquid-phase enantioseparation science for exploring enantioselective recognition mechanisms underlying enantioseparations and for identifying selector-analyte noncovalent interactions that contribute to binding and recognition. Because of the dynamic nature of the chromatographic process, molecular dynamics (MD) simulations are particularly versatile in the visualization of the three-dimensional structure of analytes and selectors and in the unravelling of mechanisms at molecular levels. In this context, MD was also used to explore enantioseparation processes promoted by amylose and cellulose-based selectors, the most popular chiral selectors for liquid-phase enantioselective chromatography. This review presents a systematic analysis of the literature published in this field, with the aim of providing the reader with a comprehensive picture about the state of the art and what is still missing for modeling cellulose benzoates and the phenylcarbamates of amylose and cellulose and related enantioseparations with MD. Furthermore, advancements and outlooks, as well as drawbacks and pitfalls still affecting the applicability of MD in this field, are also discussed. The importance of integrating theoretical and experimental approaches is highlighted as an essential strategy for profiling mechanisms and noncovalent interaction patterns.
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Affiliation(s)
| | | | | | - Paola Peluso
- Unit of Enantioselective Chromatography and Molecular Recognition, Institute of Biomolecular Chemistry ICB, Secondary Branch of Sassari, CNR, Traversa La Crucca 3, Regione Baldinca, Li Punti, 07100 Sassari, Italy; (R.D.); (A.D.); (B.S.)
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Tsui HW, Hsieh CH, Zhan CF. Effect of mobile-phase modifiers on the enantioselective retention behavior of methyl mandelate with an amylose 3,5-dimethylphenylcarbamate chiral stationary phase under reversed-phase conditions. J Sep Sci 2023; 46:e2200651. [PMID: 36401614 DOI: 10.1002/jssc.202200651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/21/2022]
Abstract
In this study, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, acetone, and tert-butanol were used as organic modifiers in reversed-phase mode chiral liquid-chromatography to systematically investigate the effects of mobile phase components on the enantioselective retention behavior of methyl mandelate with immobilized amylose 3,5-dimethylphenylcarbamate-based sorbent called Chiralpak IA. A two-site enantioselective model was used to obtain information on the recognition mechanisms by observing the dependence of the enantioselectivity and retention factor difference on the modifier content. Similar enantioselective retention behaviors were observed for all modifiers, and characteristic modifier concentration points (PL , PM , and PH ) were identified. At modifier concentrations up to PM , the weakened hydrophobic environment resulted in polymer structural relaxation, which changed the recognition mechanisms. By contrast, at concentrations beyond PH , considerably different enantioselectivity behaviors were observed, indicating that the existence of dipole-dipole interaction, which was stronger at higher modifier concentrations, contributed to the retention mechanisms. The concentrations at which these characteristic points occurred were dependent on the carbon number of the modifier molecule. Modifiers with more carbon numbers facilitated the transition in the enantioselective behaviors. These results demonstrated that the proposed method can provide a physically consistent quantitative description of enantioselective retention behavior in reversed-phase mode.
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Affiliation(s)
- Hung-Wei Tsui
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan
| | - Ching-Hung Hsieh
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan
| | - Chao-Fu Zhan
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan
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Chiral Monolithic Silica-Based HPLC Columns for Enantiomeric Separation and Determination: Functionalization of Chiral Selector and Recognition of Selector-Selectand Interaction. Molecules 2021; 26:molecules26175241. [PMID: 34500675 PMCID: PMC8434329 DOI: 10.3390/molecules26175241] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/25/2022] Open
Abstract
This review draws attention to the use of chiral monolithic silica HPLC columns for the enantiomeric separation and determination of chiral compounds. Properties and advantages of monolithic silica HPLC columns are also highlighted in comparison to conventional particle-packed, fused-core, and sub-2-µm HPLC columns. Nano-LC capillary monolithic silica columns as well as polymeric-based and hybrid-based monolithic columns are also demonstrated to show good enantioresolution abilities. Methods for introducing the chiral selector into the monolithic silica column in the form of mobile phase additive, by encapsulation and surface coating, or by covalent functionalization are described. The application of molecular modeling methods to elucidate the selector–selectand interaction is discussed. An application for enantiomeric impurity determination is also considered.
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Jameson CJ, Wang X, Murad S. Molecular dynamics simulations of enantiomeric separations as an interfacial process in
HPLC. AIChE J 2021. [DOI: 10.1002/aic.17143] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Cynthia J. Jameson
- Department of Chemistry University of Illinois at Chicago Chicago Illinois USA
| | - Xiaoyu Wang
- Department of Chemical and Biological Engineering Illinois Institute of Technology Chicago Illinois USA
| | - Sohail Murad
- Department of Chemical and Biological Engineering Illinois Institute of Technology Chicago Illinois USA
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Tsui HW, Chou PY, Ye PW, Chen SC, Chen YW. Effects of the Sorbent Backbone and Side Chain on Retention Mechanisms Using Immobilized Polysaccharide-Based Stationary Phases in Normal Phase Mode. Chromatographia 2020. [DOI: 10.1007/s10337-020-03898-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Zhao B, Oroskar PA, Wang X, House D, Oroskar A, Oroskar A, Jameson C, Murad S. The Composition of the Mobile Phase Affects the Dynamic Chiral Recognition of Drug Molecules by the Chiral Stationary Phase. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:11246-11256. [PMID: 28826215 DOI: 10.1021/acs.langmuir.7b02337] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
More than half of all pharmaceuticals are chiral compounds. Although the enantiomers of chiral compounds have the same chemical structure, they can exhibit marked differences in physiological activity; therefore, it is important to remove the undesirable enantiomer. Chromatographic separation of chiral enantiomers is one of the best available methods to get enantio-pure substances, but the optimization of the experimental conditions can be very time-consuming. One of the most widely used chiral stationary phases, amylose tris(3,5-dimethylphenyl carbamate) (ADMPC), has been extensively investigated using both experimental and computational methods; however, the dynamic nature of the interaction between enantiomers and ADMPC, as well as the solvent effects on the ADMPC-enantiomer interaction, are currently absent from models of the chiral recognition mechanism. Here we use QM/MM and molecular dynamics (MD) simulations to model the enantiomers of flavanone on ADMPC in either methanol or heptane/2-propanol (IPA) (90/10) to elucidate the chiral recognition mechanism from a new dynamic perspective. In atomistic MD simulations, the 12-mer model of ADMPC is found to hold the 4/3 left-handed helical structure in both methanol and heptane/IPA (90/10); however, the ADMPC polymer is found to have a more extended average structure in heptane/IPA (90/10) than in methanol. This results from the differences in the distribution of solvent molecules close to the backbone of ADMPC leads to changes in the distribution of the (φ, ψ) dihedral angles of the glycoside bond (between adjacent monomers) that define the structure of the polymer. Our simulations have shown that the lifetime of hydrogen bonds formed between ADMPC and flavanone enantiomers in the MD simulations are able to reproduce the elution order observed in experiments for both the methanol and the heptane/IPA solvent systems. Furthermore, the ratios of hydrogen-bonding-lifetime-related properties also capture the solvent effects, in that heptane/IPA (90/10) is found to make the separation between the two enantiomers of flavanone less effective than methanol, which agrees with the experimental separation factors of 0.9 versus 0.4 for R/S, respectively.
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Affiliation(s)
- Binwu Zhao
- Orochem Technologies, Inc., 340 Shuman Boulevard, Naperville, Illinois 60563, United States
| | - Priyanka A Oroskar
- Orochem Technologies, Inc., 340 Shuman Boulevard, Naperville, Illinois 60563, United States
| | - Xiaoyu Wang
- Department of Chemical Engineering, Illinois Institute of Technology , 10 West 33rd Street, Perlstein Hall, Chicago, Illinois 60616, United States
| | - David House
- Orochem Technologies, Inc., 340 Shuman Boulevard, Naperville, Illinois 60563, United States
| | - Anil Oroskar
- Orochem Technologies, Inc., 340 Shuman Boulevard, Naperville, Illinois 60563, United States
| | - Asha Oroskar
- Orochem Technologies, Inc., 340 Shuman Boulevard, Naperville, Illinois 60563, United States
| | - Cynthia Jameson
- Department of Chemical Engineering, University of Illinois at Chicago , 810 South Clinton Street, Chicago, Illinois 60607, United States
| | - Sohail Murad
- Department of Chemical Engineering, Illinois Institute of Technology , 10 West 33rd Street, Perlstein Hall, Chicago, Illinois 60616, United States
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