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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 449-456 
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography (SFC) ; Packed columns ; Pressure drop ; Selectivity ; Resolution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of pressure drop on retention, selectivity, plate height and resolution was investigated systematically in packed supercritical fluid chromatography (SFC) using pure carbon dioxide as the mobile phase. Numerical methods developed previously which enabled the prediction of pressure gradients, diffusivities, capacity factors, plate heights and resolutions along the length of the column were used for the model calculations. The effects of inlet pressure and supercritical fluid flow rate on selectivity and resolution are studied. In packed column SFC with pure carbon dioxide as the mobile phase, the pressure drop can have a significant effect on resolution. The flow rate is shown to have a larger effect than generally realized. The calculated data are shown to be in good agreement with the experimental results. Finally, the variation of the chromatographic parameters along a 5.5 meter long model SFC column is illustrated. The possibilities and limitations of using long packed columns in SFC are discussed. It is demonstrated that long columns with large plate numbers do not necessarily yield better separations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 483-489 
    ISSN: 0935-6304
    Keywords: Supercritical-Fluid Extraction (SFE) ; Supercritical-Fluid Chromatography (SFC) ; Recovery ; Optimization ; Retention Data ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The possibility of using supercritical-fluid chromatographic retention data for examining the effects of operational parameters, such as pressure and flow rate, on the extraction characteristics in supercritical-fluid extraction (SFE) was investigated. A model was derived for calculating the extraction efficiency in SFE from retention data and peak shapes measured in supercritical-fluid chromatography (SFC). By performing the SFC experiments at the same pressure and temperature as the SFE extractions using the SFE extraction cell as the SFC column, an accurate prediction of extraction efficiencies could be made. Finally, the effects of matrix composition and analyte concentration on extraction efficiency were studied.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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