Enantiomeric Separation with Sodium Dodecanoyl-L-amino Acidate Micelles and Poly(sodium (10-undecenoyl)-L-valinate) by Electrokinetic Chromatography

Dobashi, Akira; Hamada, Masaki; Dobashi, Yoshinori; Yamaguchi, Junko

doi:10.1021/ac00113a040

Cited by 91 publications

(53 citation statements)

References 14 publications

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“…The electrostatic repulsion between the carboxylate anions may lessen the coherent interaction between the amino acid residues with a consequent interior region hydrophobicity in the polymers. Polymer 3 and copolymer (3,5), containing the vinylacetyl-Lvaline moiety, did not dissolve in the buffer at room temperature, and thus were not used in subsequent experiments. Although polymers 2 and 3 differ by the presence of only one carbon at the linkage between the L-amino acid residue and the carbon backbone, the change in solubility was still significant.…”

Section: Polymer Solubility and Preparation Of Migrating Solution Formentioning

confidence: 99%

“…1,2 Micelles formed spontaneously by ionic surfactants 3,4 and ionic micelle-like polymers [5][6][7][8] function as well as pseudostationary phases in EKC. The solute retentivity and separability in macromolecules may be explained as being due to the formation of hydrophobic interior regions and the solute distribution within these regions.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Chiral Separation by Electrokinetic Capillary Chromatography Using Newly Synthesized Linear Polymers Containing l-Amino Acid Moieties

Hamada

Dobashi

2002

ANAL. SCI.

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Electrokinetic capillary chromatography (EKC) is an advanced technique for determining whether ionic macromolecules, in which solutes are distributed from the bulk aqueous phase, undergo separation.1,2 Micelles formed spontaneously by ionic surfactants 3,4 and ionic micelle-like polymers 5-8 function as well as pseudostationary phases in EKC. The solute retentivity and separability in macromolecules may be explained as being due to the formation of hydrophobic interior regions and the solute distribution within these regions. [9][10][11] In the present study, chiral linear polymers derived from Nacryloyl-L-amino acid derivatives were found to aggregate in aqueous solution, and the polymers to enantioselectively take in racemic amino acid derivatives during the EKC separation process. Various chiral polymers have been prepared by the thermal telomerization of N-acryloyl-L-valine and N-acryloyl-Lalanine derivatives using 3-mercaptopropionic acid (3-MPA) as a radical transfer agent. 12 For two series of polymers, the derivatives used were methyl and tert-butyl esters to obtain carboxylic acid, which was subsequently cleaved, with Nmethylamide presumably remaining in the polymer. Amino acid residues of polymers are lined up repeatedly on straight carbon backbones formed by the polymerization of acryloyl groups, as is apparent from Fig. 1. The elongation of a monomer that determines the molecular weights of the resulting polymers was controlled by mixing the ratios of the amino acid derivatives to 3-MPA. Removal of the ester groups from both types of unimolecular polymers and copolymers rendered them water-soluble. Dissociation in the carboxylic acid present in the residues should change according to the pH of the migrating solution, and thus aggregation of the polymers that permits enantiomer absorption may be controlled by electric repulsion between these functional groups. The pH dependence is discussed based on the microscopic hydrophobicity, as assessed from the fluorescence of pyrene adsorbed onto the polymers in water. ExperimentalEKC was conducted using a Model 270A capillary electrophoresis system (PE Applied Biosystems, Tokyo, Japan). Chromatography was carried out at 25˚C using fused-silica tubing (50 µm i.d. × 70 cm, 50 cm effective length; PE Applied Biosystems). Methanol was used as the sample solvent, and the sample solution was injected hydrodynamically into a capillary over a period of 0.2 s. The polymer hydrophobicity was determined from the intensity ratio of the pyrene emission peak at 383 nm (I383) relative to that at 373 nm (I373) (I383/I373) in a 2.0 w/v% aqueous solution saturated with pyrene. Pyrene was excited at 337 nm and its fluorescence spectrum was measured with a fluorospectrophotometer (FP-777; JASCO, Tokyo, Japan) at 25˚C. 12 A 1 H-NMR measurement was made using a Varian Gemini-300 (300 MHz NMR). The internal standard was chloroform (7.26 ppm) in a deuteriochloroform solution. Preparation of N-acryloyl-L-alanine methyl ester (monomer 1), N-acryloyl-L-valine methyl ester (monomer 2a) ...

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Section: Polymer Solubility and Preparation Of Migrating Solution Formentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chiral Separation by Electrokinetic Capillary Chromatography Using Newly Synthesized Linear Polymers Containing l-Amino Acid Moieties

Hamada

Dobashi

2002

ANAL. SCI.

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“…It should be noted that some patents have also been reported on polymeric surfactants (34,35). (33,36). Wang and Warner demonstrated numerous advantages of polymeric surfactants over conventional nonpolymerized micelles, while Dobashi provided a detailed comparison to conventional micelles.…”

Section: A Ac Ch Hi Ir Ra Al L P Po Ol Ly Ym Me Er Rs Smentioning

confidence: 99%

“…Therefore, it is reasonable to expect a faster rate of solute mass transfer into and out of the polymeric surfactant. The work of Dobashi's and Warner's groups has extended the applicability of this polymeric system for chiral separations (3,36). D Di ip pe ep pt ti id de e p po ol ly ym me er ri ic c s su ur rf fa ac ct ta an nt ts s. .…”

Section: A Ac Ch Hi Ir Ra Al L P Po Ol Ly Ym Me Er Rs Smentioning

confidence: 99%

Peer Reviewed: Molecular Micelles: Novel Pseudostationary Phases for CE

Shamsi¹,

Palmer²,

Warner³

2001

Anal. Chem.

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“…In comparison with chiral HPLC separations capillary electrophoresis offers a more straightforward separations which are more easy to interpret as long as the interactions allowing for stereoisomer separations occur directly with a chiral selector added to the background electrolyte. The most common chiral selectors are optically active micelles [142], cyclodextrins [143][144][145][146], derivatized cyclodextrins [147,148], ligand exchangers [149], macrocyclic antibiotics [150,151], polymeric stereoselective modifiers [152], glycosaminoglycans [153], and crown ethers [154][155][156][157][158][159]. In some instances the chiral selector has been bound to the capillary wall or included into a gel [140].…”

Section: Chiral Separationsmentioning

confidence: 99%

Advances in capillary electrophoresis

Deyl

Mikšı́k

Tagliaro

1998

Forensic Science International

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This review summarizes the advancement in operational modes and selected applications of the title technique over the past five years. Regarding operational modes particular emphasis is put upon increasing selectivity and resolution, hyphenation of capillary electrophoresis with techniques based on other than electromigration principles, the so-called chip technology and new ways of detection. In applications selected examples of chiral separations and separation of biopolymers (proteins, nucleic acids) are emphasized. It is demonstrated that capillary electrophoresis represents a complementary technique to high-performance column chromatography and in a number of cases it offers better separations than standard chromatographic procedures.

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Enantiomeric Separation with Sodium Dodecanoyl-L-amino Acidate Micelles and Poly(sodium (10-undecenoyl)-L-valinate) by Electrokinetic Chromatography

Cited by 91 publications

References 14 publications

Chiral Separation by Electrokinetic Capillary Chromatography Using Newly Synthesized Linear Polymers Containing l-Amino Acid Moieties

Chiral Separation by Electrokinetic Capillary Chromatography Using Newly Synthesized Linear Polymers Containing l-Amino Acid Moieties

Peer Reviewed: Molecular Micelles: Novel Pseudostationary Phases for CE

Advances in capillary electrophoresis

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