ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 2
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Functional group selectivity using fluoroform as a mobile phase for supercritical fluid chromatography (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 6 (1994), S. 475-482 
    Details
    ISSN: 1040-7685
    Keywords: supercritical fluid chromatography ; fluoroform ; carbon dioxide ; mobile phases ; selectivity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The eluotropic strenght and chromatographic selectivity of fluoroform is compared to that of carbon dioxide and methanol-modified carbon dioxide. Naphthalene derivatives were used as probe solutes in capillary supercritical fluid chromatography to determine the effects of fluid type, pressure, and temperature on selectivity and retention. Fluoroform is much stronger in eluotropic strengh than carbon dioxide or methanol-modified carbon dioxide at the same temperature and pressure. Under the same reduced conditions, fluoroform is lower in eluotropic strength than carbon dioxide. Specific interactions between hydrogen bond accepting functional groups and fluoroform are observed. Functional groups capable of accepting hydrogen bonds contribute less of an increase in retention when using fluoroform while those capable of dispersive interactions contribute less of an increase in retention when using carbon dioxide.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220060507
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...