• Title/Summary/Keyword: Chiral Separation

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A Novel Design of Simulated Moving Bed (SMB) Chromatography for Separation of Ketoprofen Enantiomer

  • Yoon, Tae-Ho;Chung, Bong-Hyun;Kim, In-Ho
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.9 no.4
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    • pp.285-291
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    • 2004
  • A simulated moving bed (SMB) chromatography system is a powerful tool for preparative scale separation, which can be applied to the separation of chiral compound. We have de-signed our own lab-scale SMB chromatography using 5 HPLC pumps, 6 stainless steel columns and 4 multi-position valves, to separate a racemic mixture of ketoprofen in to its enantiomers. Our design has the characteristics of the low cost for assembly for the SMB chromatography and easy repair of the unit, which differs from the designs suggested by other investigators. It is possible for the flow path through each column to be independently changed by computer control, using 4 multi-position rotary valves and 5 HPLC solvent delivery pumps. In order to prove the operability of our SMB system, attempts were made to separate the (S)-ketoprofen enantiomer from a ketoprofen racemic mixture. The operating parameters of the SMB chromatography were calculated for ketoprofen separation from a batch chromatography experiment as well as by the triangle theory. With a feed concentration of 1 mg/mL, (S)-ketoprofen was obtained with a purity of 96% under the calculated operating conditions.

A Newly Developed Analytical and Semi-preparative Enantiomer Separation of Fluoxetine using Polysaccharide-derived Chiral Stationary Phases by High Performance Liquid Chromatography (고성능 액체 크로마토그래피에 의한 다당 유도체의 키랄 고정상에서 플록세틴의 새롭게 개발된 분석 및 반분취의 광학분리)

  • Kim, Seok Jin;Nam, Kyung Wook;Park, Bohyun;Islam, Md. Fokhrul;Lee, Wonjae
    • KSBB Journal
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    • v.31 no.3
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    • pp.186-191
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    • 2016
  • A liquid chromatographic method for the enantiomer separation of fluoxetine was performed using covalently bonded and coated type polysaccharide-derived chiral stationary phases (CSPs). The degree of enantioseparation is affected by the used CSPs and mobile phases. The performance of Chiralpak IC was superior to the other CSPs used in this study. Out of various solvent composition and additives, the greatest separation and resolution was observed using Chiralpak IC with mobile phase of 2-propanol in hexane with diethylamine as an additive. Semi-preparative separation of fluoxetine was performed on the analytical Chiralpak IC column to obtain (R)- and (S)-fluoxetine enantiomer with high chemical and optical purity. From the overall study, the developed liquid chromatographic method on polysaccharide-derived CSPs is expected to be very useful for the enantiomer separation of fluoxetine.

Two-dimensional Chiral Honeycomb Structures of Unnatural Amino Acids on Au(111)

  • Yang, Sena;Jeon, Aram;Lee, Hee-Seung;Kim, Sehun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.191.1-191.1
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    • 2014
  • Crystallization has become the most popular technique for the separation of enantiomers since the Pasteur's discovery. To investigate mechanism of crystallization of chiral molecules, it is necessary to study self-assembled structures on two-dimensional surface. Here, we have studied two-dimensional self-assembled structures of an unnatural amino acid, (S)-${\beta}$-methyl naphthalen-1-${\gamma}$-aminobutyric acid (${\gamma}^2$-1-naphthylalanine) on Au(111) surface at 150 K using scanning tunneling microscopy (STM). At initial stage, we found two chiral honeycomb structures which are counter-clockwise and clockwise configurations in one domain. The molecules are arranged around molecular vacancies, dark hole. By further increasing the amounts of adsorbed ${\gamma}^2$-1-naphthylalanine, a well-ordered square packed structure was observed. In addition, we found the other structure that molecules were trapped in the pore of the hexagonal molecular assembly.

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Enantioseparation of Neutral Compounds on a Quinine Carbamate-Immobilized Zirconia in Reversed-Phase Capillary Electrochromatography

  • Lee, Mun-Rak;Gwon, Ju-Rim;Park, Jung-Hag
    • Bulletin of the Korean Chemical Society
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    • v.31 no.1
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    • pp.82-86
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    • 2010
  • Quinine (QN) is a weak anion-exchange type chiral selector and QN-based silica stationary phases have been widely used for enantioseparation of acidic chiral analytes in HPLC and recently in CEC. In this work we report enantioseparation of non-acidic chiral analytes on a quinine carbamate-immobilized zirconia (QNZ) in reversed-phase (RP) CEC. Influences of pH, composition of the buffer, acetonitrile content and the applied voltage on enantioseparation were examined. Enantiomers of the analytes investigated are well separated in acetonitrile/phosphate buffer mobile phases. Separation data on QNZ were compared to those on QN-bonded silica (QNS). Retention was longer but better enantioselectivity and resolution were obtained on QNZ than QNS.

Molecular Modeling of the Chiral Recognition of Propranolol Enantiomers by a β-Cyclodextrin

  • Kim, Hyun-myung;Jeong, Karp-joo;Lee, Sang-san;Jung, Seun-ho
    • Bulletin of the Korean Chemical Society
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    • v.24 no.1
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    • pp.95-98
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    • 2003
  • Enantioselectivity of the propranolol on β-cyclodextrin was simulated by molecular modeling. Monte Carlo (MC) docking and molecular dynamics (MD) simulations were applied to investigate the molecular mechanism of enantioselective difference of both enantiomeric complexes. An energetic analysis of MC docking simulations coupled to the MD simulations successfully explains the experimental elution order of propranolol enantiomers. Molecular dynamics simulations indicate that average energy difference between the enantiomeric complexes, frequently used as a measure of chiral recognition, depends on the length of the simulation time. We found that, only in case of much longer MD simulations, noticeable chiral separation was observed.