Comparison of Chiral Recognition of Binaphthyl Derivatives with l-Undecyl-Leucine Surfactants in the Presence of Arginine and Sodium Counterions

Ramos, Zoe; Rothbauer, Gabriel A; Turner, Johnathan; Lewis, Corbin R.; Morris, Kevin; Billiot, Eugene; Billiot, Fereshteh; Fang, Yayin

doi:10.1093/chromsci/bmy080

Cited by 10 publications

(16 citation statements)

References 27 publications

(46 reference statements)

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“…MEKC using chiral bile salts benefits from their commercial availability [145]; mainly sodium cholate, sodium deoxycholate, sodium taurocholate, and sodium deoxytaurocholate have been employed [140]. The use of other nonbile chiral surfactants has also been successfully reported, including amino acid based surfactants [146] and vesicle-forming cationic surfactants [147]. Additionally, a trend has been observed in recent years toward the implementation of polymeric micelles in chiral MEKC [140].…”

Section: Surfactantsmentioning

confidence: 99%

Past, present, and future developments in enantioselective analysis using capillary electromigration techniques

2020

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Past, present, and future developments in enantioselective analysis using capillary electromigration techniques Enantioseparation of chiral products has become increasingly important in a large diversity of academic and industrial applications. The separation of chiral compounds is inherently challenging and thus requires a suitable analytical technique that can achieve high resolution and sensitivity. In this context, CE has shown remarkable results so far. Chiral CE offers an orthogonal enantioselectivity and is typically considered less costly than chromatographic techniques, since only minute amounts of chiral selectors are needed. Several CE approaches have been developed for chiral analysis, including chiral EKC and chiral CEC. Enantioseparations by EKC benefit from the wide variety of possible pseudostationary phases that can be employed. Chiral CEC, on the other hand, combines chromatographic separation principles with the bulk fluid movement of CE, benefitting from reduced band broadening as compared to pressure-driven systems. Although UV detection is conventionally used for these approaches, MS can also be considered. CE-MS represents a promising alternative due to the increased sensitivity and selectivity, enabling the chiral analysis of complex samples. The potential contamination of the MS ion source in EKC-MS can be overcome using partial-filling and counter-migration techniques. However, chiral analysis using monolithic and open-tubular CEC-MS awaits additional method validation and a dedicated commercial interface. Further efforts in chiral CE are expected toward the improvement of existing techniques, the development of novel pseudostationary phases, and establishing the use of chiral ionic liquids, molecular imprinted polymers, and metalorganic frameworks. These developments will certainly foster the adoption of CE(-MS) as a well-established technique in routine chiral analysis.

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Section: Surfactantsmentioning

confidence: 99%

Past, present, and future developments in enantioselective analysis using capillary electromigration techniques

2020

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“…However, the enantiomers differ in stereoconfiguration, which allows them to interact differently with chiral separation mediums, thus allowing for enantioseparation [5]. Some commonly used chiral separation techniques are high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE), which utilize chiral stationary and pseudostationary phases, respectively [7] [8]. In using chiral chromatographic techniques, if the two enantiomers of a chiral compound, the R-and S-enantiomer, have different binding affinities to the chiral separation medium, then enantiomeric separations can occur.…”

Section: Introductionmentioning

confidence: 99%

Chiral Recognition of Dansyl Derivatives with an Amino Acid-Based Molecular Micelle: A Molecular Dynamics Investigation

Mauro¹,

Black²,

Billiot³

et al. 2021

OJPC

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In this study, the chiral separation mechanisms of Dansyl amino acids, including Dansyl-Leucine (Dans-Leu), Dansyl-Norleucine (Dans-Nor), Dansyl-Tryptophan (Dans-Trp) and Dansyl-Phenylalanine (Dans-Phe) binding to poly-sodium N-undecanoyl-(L)-Leucylvalinate, poly (SULV), were investigated using molecular dynamics simulations. Micellar electrokinetic chromatography (MEKC) has previously shown that when separating the enantiomers of these aforementioned Dansyl amino acids, the L-enantiomers bind stronger to poly (SULV) than the D-enantiomers. This study aims to investigate the molecular interactions that govern chiral recognition in these systems using computational methods. This study reveals that the computationally-calculated binding free energy values for Dansyl enantiomers binding to poly (SULV) are in agreement with the enantiomeric order produced in experimental MEKC studies. The L-enantiomers of Dans-Leu, Dans-Nor, Dans-Trp, and Dans-Phe binding to their preferred binding pockets in poly (SULV) yielded binding free energy values of −21.8938, −22.1763, −21.3329 and −13.3349 kJ•mol −1 , respectively. The D-enantiomers of Dans-Leu, Dans-Nor, Dans-Trp, and Dans-Phe binding to their preferred binding pockets in poly (SULV) yielded binding free energy values of −14.5811, −15.9457, −13.6408, and −12.0959 kJ•mol −1 , respectively. Furthermore, hydrogen bonding analyses were used to investigate and elucidate the molecular interactions that govern chiral recognition in these molecular systems.

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“…Furthermore, covalently bound surfactants are in micellar form at all concentrations, whereas conventional surfactants only form micelles above their CMC (critical micelle concentration). This property allows separations to be carried out at lower concentrations often leading to improvements in chiral selectivity [13]- [19].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Amino Acid Based Molecular Micelles with Molecular Modeling

Billiot

Fang

Morris

2019

OJPC

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The enantiomers of chiral drugs often have different potencies, toxicities, and biochemical properties. Therefore, the FDA and other worldwide regulatory agencies require manufactures to test and prove the enantiomeric purity of chiral drugs. Amino acid based molecular micelles (AABMM) have been used in chiral CE separations since the 1990's because of their low environmental impact and because their properties can easily be tuned by changing the amino acids in the chiral surfactant head groups. Using molecular dynamics simulations to investigate the structures and properties of AABMM is part of an ongoing study focusing on investigating and elucidating the factors responsible for chiral recognition with AABMM. The results will be useful for the proper design and selection of more efficient chiral selectors. The micelles investigated contained approximately twenty covalently linked surfactant monomers. Each monomer was in turn composed of an undecyl hydrocarbon chain bound to a dipeptide headgroup containing of all combinations of L-Alanine, L-Valine, and L-Leucine. These materials are of interest because they are effective chiral selectors in capillary electrophoresis separations. Molecular dynamics simulation analyses were used to investigate how the sizes and positions of the headgroup amino acid R-groups affected the solvent accessible surface areas of each AABMM chiral center. In addition, headgroup dihedral angle analyses were used to investigate how amino acid R-group size and position affected the overall headgroup conformations. Finally, distance measurements were used to study the structural and conformational flexibilities of each AABMM headgroup. All analyses were performed in the context of a broader study focused on developing structure-based predictive tools to identify the factors responsible for a) self-assembly, b) function, c) higher ordered structure and d) molecular recognition of these amino acid based mo-How to cite this paper: Billiot, A., Fang,

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Comparison of Chiral Recognition of Binaphthyl Derivatives with l-Undecyl-Leucine Surfactants in the Presence of Arginine and Sodium Counterions

Cited by 10 publications

References 27 publications

Past, present, and future developments in enantioselective analysis using capillary electromigration techniques

Past, present, and future developments in enantioselective analysis using capillary electromigration techniques

Chiral Recognition of Dansyl Derivatives with an Amino Acid-Based Molecular Micelle: A Molecular Dynamics Investigation

Characterization of Amino Acid Based Molecular Micelles with Molecular Modeling

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