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  • 1
    Electronic Resource
    Electronic Resource
    Application of Subcritical Fluid Chromatography to Rapid Chiral Method Development (1994)
    s.l. : American Chemical Society
    Analytical chemistry 66 (1994), S. 1949-1954 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac00085a005
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Monitoring Formation of a Diamine Process Intermediate by Reversed-Phase Liquid Chromatography (1994)
    s.l. : American Chemical Society
    Analytical chemistry 66 (1994), S. 4370-4374 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac00095a039
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Relationship between resolution and analysis time in chiral subcritical fluid chromatography (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 249-257 
    Details
    ISSN: 0899-0042
    Keywords: chiral SubFC resolution ; analysis time ; column efficiency ; library of chiral columns ; selectivity ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A model is presented that predicts a defined relationship between chiral SubFC resolution and analysis time. This model is based upon ideal chromatographic behavior and requires column efficiency and selectivity to be independent of mobile phase modifier level and flow rate. The validity of these assumptions was found to be imperfect but acceptable for two model compounds on two commonly used chiral columns.A major implication of the model is that the maximum resolution obtainable with a particular column and mobile phase modifier may be predicted from one injection. The retention time required to obtain a desired resolution is also calculable. This information enables the practitioner to discern quickly the futility of method development efforts. Insufficient maximum resolution predicted from the first injection would require an increase in selectivity to achieve a useful separation. Selectivity may then be altered by temperature, modifier, or stationary phase. The increased column efficiency of SubFC at typical flow rates rescues separations that fail by HPLC, thus shrinking the practitioner's required library of chiral columns. This work demonstrates that SubFC also allows the practitioner to skim through that library very quickly. © 1996 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Temperature effects for chiral separations using various bulk fluids in near-critical mobile phases (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 9 (1997), S. 693-698 
    Details
    ISSN: 0899-0042
    Keywords: supercritical fluid chromatography ; subcritical fluid chromatography ; HFC-134a ; 1,1,1,2-tetrafluoroethane ; carbon dioxide ; chiral selectivity ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As supercritical fluid chromatography becomes more accepted as a facile means for the separation of chiral compounds, the need for mobile phases that can readily solubilize these polar compounds grows. Prior studies suggest that HFC-134a may prove suitable due to its very high eluotropic strength compared to carbon dioxide-based mobile phases. A comparison is made between ethanol-modified carbon dioxide, HFC-134a, and decafluoropentane as to their relative eluotropic strength, selectivity, and efficiency for three chiral compounds using a Whelk O-1 chiral bonded phase. The bulk component of the mobile phase was found to have relatively little effect on chiral selectivity over the range of 5° to 95°C. Chirality 9:693-698, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Effect of Mobile Phase Components on the Separation of Polypeptides Using Carbon Dioxide-Based Mobile Phases (1999)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 74-78 
    Details
    ISSN: 0935-6304
    Keywords: Polypeptides ; subcritical fluid chromatography ; supercritical fluid chromatography ; carbon dioxide ; additives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The effect of mobile phase modifier and additive on the chromatographic properties of various small polypeptides was explored under subcritical conditions. A polymeric column was used to separate various enkephalin analogs, bradykinin, and oxytocin using a carbon dioxide-based mobile phase with either an ethanol or a 2-methoxyethanol modifier. The role of the modifier was found to be secondary to that of the mobile phase additive. As progressively stronger acidic mobile phase additives were used, the peak profiles of the various polypeptides improved and retention decreased. Heptadecafluorooctanesulfonic acid was found to be the most useful additive for these types of solutes under near-critical conditions, while the potassium salt of heptadecafluorooctanesulfonic acid failed to elute any of the polypeptides. At low temperatures, pressure gradients with a carbon dioxide/ethanol/heptadecafluorooctanesulfonic acid ternary mobile phase produced reasonably good peak profiles with the polymeric column.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Comparision of varuious bulk fluids and modifiers as near-crtical mobile phases on a polymeric column using linear solvatio energy realationships (1997)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 631-637 
    Details
    ISSN: 0935-6304
    Keywords: High Perfromance liquid chromatography ; supercritical fluid chromatography ; Selectivity ; Hydrogen bonding ; Linear solvation energy relationships ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Linear solvation energy realationships (LSERS) were used to qunatitatively compare the relative contributions of dipolarity/polarizability, hydrogen bonding, and other types of intermolecular interactions to retention and selectivity using various bulk moblie phase component. Using experimental condition which differ only by the compostion of the bulk moble phase component, the factors which cause selctivity to differ between HPLC, subcritical fluid chromatography and supercritical fluid charomatography were decovoluted. Heptance-based HPLC mobile phases showed superior selectivities towards analytes which differ in hydrogen bond donating ability, gas-to-hexadecane partion coefficint and dipolarity/ploarizability. subcritical fluid chromatography with HFC-134a (1, 1, 1, 2-tetrafluoroethane) as the bulk fluid produced superior seclectivities for which differ in hydrogen bond accepting ability and execess molar refraction properties. Many of these factors showed temperature dependences which act to attenuate or accenture the particular intermolcular interaction.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240201203
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    Paper (German National Licenses)
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