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  • 1980-1984  (3)
  • Silica, modified  (2)
  • Amino groups, bonded  (1)
  • Reaction detector  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 14 (1981), S. 325-332 
    ISSN: 1612-1112
    Keywords: HPLC ; Proteins ; Silica, modified ; Exclusion chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Highly efficient and fast exclusion-chromatographic separations of proteins are possible on chemically-modified, silica stationary phases. By optimizing the pH and the ionic strength of the aqueous eluent secondary interactions of the samples with surface groups can be excluded. Bonded propylamide groups proved to possess optimum properties for exclusion chromatography. With other functional groups adsorption effects cannot be excluded totally. The optimum pore size distribution for protein separation up to relative molecular masses of 500,000 daltnons is between 10nm and 50nm. With these silica-based phases the pore size distribution, the pore volume and the packing characteristics are independent of the eluent, therefore the same column can be used with aqueous as well with organic eluents. It is possible to correlate the elution volume (molecular size) of proteins with those of polystyrene standars. The recovery of the proteins and their biological activity has always been better than 90%. The potentialities of adsorption chromatography of proteins on chemically-bonded stationary plases with different functional groups are demonstrated.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 15 (1982), S. 91-96 
    ISSN: 1612-1112
    Keywords: Amino groups, bonded ; Silica, modified ; Sugars
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Zuckertrennung mit chemisch gebundenen Aminophasen beruht auf einer Verteilung der Proben zwischen einer stehenden wäßrigen Phase und dem bewegten Eluenten, einem Acetonitril-Wasser-Gemisch. Die Aufspaltung des Eluenten in zwei Phasen ist auf die gebundenen Aminogruppen zurückzuführen, die sonst nicht an der Trennung beteiligt sind. Mit der Aminophase erhält man so eine Belegung von 0,15 g/g stationärer Phase. Die Belegung steigt mit zunehmendem Stickstoffgehalt der gebundenen Phase. Bei der Triamiphase erhält man eine Belegung von 0,25 g/g. Die k'-Werte der Proben steigen — bei gleicher Eluentenzusammensetzung — mit der Wasserbelegung an. Daher kann zur Reduzierung der Analysenzeit, bei identischer Auflösung, der Wassergehalt im Eluenten bis auf das Doppelte-verglichen mit der Aminphase-erhöht werden. Dies erleichtert die Zuckeranalyse, da die Löslichkeit der Proben im Eluenten steigt.
    Notes: Summary The speration of sugars with chemically bonded amino groups depends on the partition of the solutes between a stagnant aqueous liquid phase and a moving acetonitrile-water mixture. The bonded amino groups cause demixing of the aqueous acetonitrile eluent, but do not otherwise participate in the separation process. With amino groups a liquid loading of 0.15 g/g is achieved. The loading increases with increasing nitrogen content of the bonded phase. With triamino phases liquid loadings of 0.25 g/g are obtained. At constant eluent composition the k' values increase with increasing water loading. With the triamino phase the water concentration in the eluent can be doubled compared to that with the standard amino phase to achieve identical resolution and analysistime. This facilitates the sugar analysis owing to the increased solubility of the solute in the eluent.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 15 (1982), S. 403-408 
    ISSN: 1612-1112
    Keywords: Liquid chromatography ; Reaction detector ; Colorimetric detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A reaction detector with non-segmented flow in open tubes as reaction track is described. To minimize peak broadening the open tubes are arranged in a three dimensional coiled structure by knitting. At low volume flow rates the h-values in these open tubes are independent of flow rate and are significantly lower than predicted by theory. The applicability of this reactor for classical colorimetric detection with corrosive reagents is shown.
    Type of Medium: Electronic Resource
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