Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    ISSN: 1612-1112
    Keywords: Supercritical fluid chromatography ; Mixed mobile phases ; Capillary and packed columns ; Antibiotics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The separation of polar thermally labile solutes is one of the potentially most rewarding fields of SFC application. A presupposition for such applications is, however, mobile phases having relatively high solvent strengths. A promising approach to achieve this is the use of mobile phases consisting of carbon dioxide with a polar additive. In this work, the chromatographic effects of different concentrations of an additive, isopropanol, in carbon dioxide have been studied on capillary and packed columns. A series of antibiotics was used as test substances. Best results were obtained with carbon dioxide/8% isopropanol as mobile phase on a capillary column coated with a cyanopropyl-substituted polysiloxane stationary phase.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 0935-6304
    Keywords: Enantiomer separation ; mixed chiral selectors ; modified cyclodextrins ; gas chromatography ; PCB ; o,p´-DDD ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Columns containing different types of cyclodextrin derivatives have been evaluated for chiral gas chromatographic separation of atropisomeric PCBs, o,p´-DDT and o,p´-DDD. Separation was attempted on columns containing mixed chiral selectors, and the performance of two closely related selectors was also examined. The cyclodextrins were: permethylated-β-CD (PM-β-CD), heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-β-CD (2,3-M-6-TBDMS-β-CD), heptakis(2,3-di-O-methyl-6-O-tert-hexyldimethylsilyl)-β-CD (2,3-M-6-THDMS-β-CD), and heptakis(2,3-di-O-ethyl-6-O-tert-hexyldimethylsilyl)-β-cyclodextrin (2,3-E-6-THDMS-β-CD). The cyclodextrins were dissolved in OV-1701 or in a dimethylsiloxane/silarylene copolymer containing 5% phenyl in the backbone. The application of mixed chiral selectors led to improved separations, however; at most eleven PCB congeners were separated on a single column. Chiral resolution of o,p´-DDD was achieved. The use of a dimethylsiloxane/silarylene copolymer as a matrix for the cyclodextrins is a promising approach. With such a matrix, blocking of the CD cavities by silicone substituent groups can be avoided, and a reasonable CD solubility can be provided. The selectivity of heptakis(2,3-di-O-ethyl-6-O-tert-hexyldimethylsilyl)-β-CD and heptakis(2,3-di-O-methyl-6-O-tert-hexyldimethylsilyl)-β-CD was quite different, the former selector could separate four congeners, while the latter separated ten congeners.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...