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  • Biochemistry and Biotechnology  (26)
  • Cyclodextrin polymer  (2)
  • Column-coupling system  (1)
  • 1
    Electronic Resource
    Electronic Resource
    A further study on the chiral separation power of a soluble neutral β-cyclodextrin polymer (1995)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 348-352 
    Details
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis ; Enantiomers ; Cyclodextrin polymer ; Organic modifiers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantiomeric separation of some basic compounds, namely selegiline, amphetamine, and clenbuterol, was studied by capillary electrophoresis using an uncharged β-cyclodextrin polymer added to the background electrolyte at pH 2.5. Both complexation and resolution were influenced by the concentration of the chiral polymer confirming our previous results obtained in our earlier work for a wide number of pharmaceutical compounds. In this further study, we examined the influence of different organic additives to the background electrolyte on the enantioselectivity of the chiral selector, also using an extended number of analytes. In most cases, the use of an organic additive resulted in a decrease of resolution. However opposite to that, in some cases, e.g. ephedrine, the organic solvent proved to be essential to achieve enantiomeric resolution. Furthermore the influence of the capillary temperature on the resolution of the analytes was evaluated. Increase of temperature had a deleterious effect on the resolution of the enantiomers. For ephedrine, however, relatively high temperature (50 °C) proved to be advantageous, for the resolution of the optical isomers.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240180605
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  • 2
    Electronic Resource
    Electronic Resource
    Capillary zone electrophoretic separation of cyclodextrins with indirect UV photometric detection (1990)
    Weinheim : Wiley-Blackwell
    Electrophoresis 11 (1990), S. 774-776 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A method for the separation of cyclodextrins by capillary zone electrophoresis with indirect detection is described. It is based on the formation of inclusion complexes with benzoate which simultaneously forms a UV absorbing constituent of the background electrolyte used for the separation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150110917
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  • 3
    Electronic Resource
    Electronic Resource
    Enantiomer resolution by using capillary zone electrophoresis: Resolution of racemic tryptophan and determination of the enantiomer composition of commercial pharmaceutical epinephrine (1990)
    Weinheim : Wiley-Blackwell
    Electrophoresis 11 (1990), S. 757-760 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The enantiomers of D- and L-tryptophan were separated by capillary electrophoresis, using α-cyclodextrin as a chiral active component in the background electrolyte. The separation of (-) and (+) epinephrine was achieved by supplementing the background electrolyte with Heptakis (2,6-di-O-methyl-β-cyclodextrin). As a practical application of the method, the quantitative analysis of (-)and(+)enantiomers in commercial pharmaceutical solutions of adrenaline is shown.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150110913
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  • 4
    Electronic Resource
    Electronic Resource
    Capillary zone electrophoresis of rare earth metals with indirect UV absorbance detection (1990)
    Weinheim : Wiley-Blackwell
    Electrophoresis 11 (1990), S. 780-783 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The separation of 14 lanthanides by capillary zone electrophoresis was studied in the background electrolyte containing hydroxyisobutyric acid as complexing counterion and creatinine as a UV absorbing coion for indirect detection of lanthanide zones. A complete separation was achieved in less than 5 min and the applicability of the method for the analysis of real samples was demonstrated.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150110919
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  • 5
    Electronic Resource
    Electronic Resource
    Enantiomers resolution in capillary zone electrophoresis by using cyclodextrins (1992)
    Weinheim : Wiley-Blackwell
    Electrophoresis 13 (1992), S. 687-690 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Cyclodextrins added to the background electrolyte are shown to be useful for the resolution of racemic compounds in their enantiomers. Several parameters have to be controlled in order to achieve resolution, e.g., cyclodextrin type, concentration, analyte shape, as well as column temperature. The resolution of nor-epinephrine, epinephrine and isoproterenol in their enantiomers decreased by increasing the column temperature. Octopamine and ketamine have been resolved by supporting the background electrolyte with 2, 6-di-O-methyl-β-cyclodextrin. In spite of the stronger inclusion-complex of ketamine than octopamine with the modified cyclodextrin its resolution was not satisfactory.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.11501301146
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  • 6
    Electronic Resource
    Electronic Resource
    Separation of α-hydroxy acid enantiomers by high performance capillary electrophoresis using copper(II)-L-amino acid and copper(II)-aspartame complexes as chiral selectors in the background electrolyte (1994)
    Weinheim : Wiley-Blackwell
    Electrophoresis 15 (1994), S. 864-869 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Optical isomers of some α-hydroxy acids, namely 2-, 3-phenyllactic acid, mandelic, p-hydroxy-, m-hydroxy and 3,4-di-hydroxymandelic acid, were separated by means of capillary zone electrophoresis in free solution, using copper (II) complexes with L-amino acid or aspartame ligands in the background electrolyte. The concentration and the pH dependence of the enantiomer separations have been studied in the cases of different chiral ligands and/or analytes. With the use of L-proline as ligand only the optical isomers of 3-phenyllactic acid were resolvable, whereas using L-hydroxyproline the D and L forms of all compounds, except for 2-phenyllactic acid, were separated. Better results were obtained with aspartame as chiral ligand.Part of this work was presented at the 5th International Symposium on High Performance Capillary Electrophoresis, January 25-28, 1993, Orlando, FL, USA.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.11501501122
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  • 7
    Electronic Resource
    Electronic Resource
    Capillary electrophoresis quantitation of l-L-folinic acid in the presence of its inactive d-L-form (1993)
    Weinheim : Wiley-Blackwell
    Electrophoresis 14 (1993), S. 823-825 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The diastereomers d-L and l-L-folinic acid were separated by capillary electrophoresis, using heptakis (2,3-di-O-methyl)-β-cyclodextrin as a chiral active component in the background electrolyte. The method proved suitable for the quantitation of these compounds in one commercial pharmaceutical preparation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.11501401129
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  • 8
    Electronic Resource
    Electronic Resource
    Separation of tryptophan-derivative enantiomers with iron-free human serum transferrin by capillary zone electrophoresis (1995)
    Weinheim : Wiley-Blackwell
    Electrophoresis 16 (1995), S. 1510-1518 
    Details
    ISSN: 0173-0835
    Keywords: Chiral separation ; Enantiomers ; Human serum transferrin Stereoselective interactions ; Capillary zone electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Enantiomers can be separated by using human serum transferrin as a chiral phase. With the help of the native protein we were able to separate enantiomers with high efficiency, using a low ionic strength 2-(N-morpholino)ethanesulfonic acid (MES) buffer, pH 6, in capillary zone electrophoresis. Tryptophan methyl, ethyl and butyl ester enantiomers - moving towards the cathode at pH 6 - were resolved by passing through an iron-free transferrin zone in coated capillaries. Since the isoelectric point of the iron-free transferrin is a little higher than 6, the protein zone is either not moving in the experiment or is slowly moving towards the anode. Under the simplest experimental conditions the highest resolution was obtained for the butyl ester enantiomers and the lowest for the methyl ester ones. By changing the experimental conditions, however, this order could be reversed. The results indicate that the lengths of the alkyl chains in the enantiomers have a significant effect on the resolution, i.e., on the interaction between the protein and the separands.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.11501601250
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  • 9
    Electronic Resource
    Electronic Resource
    Further study on the use of uncharged β-cyclodextrin polymer in capillary electrophoresis: Enantiomeric separation of some α-hydroxy acids (1995)
    Weinheim : Wiley-Blackwell
    Electrophoresis 16 (1995), S. 1505-1509 
    Details
    ISSN: 0173-0835
    Keywords: Enantiomers ; Capillary electrophoresis ; Cyclodextrin polymer ; α-Hydroxy acids ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Uncharged β-cyclodextrin polymer was used as chiral selector for the enantiomeric separation of some α-hydroxy acids by capillary electrophoresis. Complexation and enantiomeric resolution of mandelic acid, m-hydroxy and p-hydroxymandelic acid, 3,4-dihydroxymandelic acid, as well as 2- and 3-phenyllactic acid were studied, changing the concentration of the β-cyclodextrin polymer added to the background electrolyte at different pH in the range of 4.5-7. Furthermore, the effects of the concentration of the background electrolyte, column temperature, and applied voltage on chiral resolution were also examined. The best enantiomeric separations were obtained using a background electrolyte at pH 6 containing 100 mg/mL of β-cyclodextrin polymer.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.11501601249
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  • 10
    Electronic Resource
    Electronic Resource
    A practical procedure for the determination of association constants of the analyte-chiral selector equilibria by capilllary zone electrophoresis (1996)
    Weinheim : Wiley-Blackwell
    Electrophoresis 17 (1996), S. 1921-1924 
    Details
    ISSN: 0173-0835
    Keywords: Capillary zone electrophoresis ; Chiral separations ; Association constants ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A practical procedure is proposed for the determination of association constants and mobility of the associate of a solute with a chiral selector in chiral separations by capillary zone electrophoresis. The procedure is based on the measurement of the effective mobility of a solute at zero and two different nonzero concentrations of the chiral selector. Simple explicit formulas have been derived in order to calculate the required data. The essence of the procedure is that all mobility data are adjusted to the background electrolyte (BGE) without chiral selector, serving as the viscosity reference. A simple procedure is described for measuring the viscosity of the operational electrolytes directly with the commercial capillary electrophoresis instrumentation, and Walden's rule has been utilized for adjusting the experimental mobility data to constant reference viscosity. The use of the procedure is exemplified by a separation of D,L-tryptophan in BGE containing α-cyclodextrin as chiral selector.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150171219
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