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  • 1
    Electronic Resource
    Electronic Resource
    Theory of fast capillary gas chromatography. Part 1: Column efficiency (1997)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 597-604 
    Details
    ISSN: 0935-6304
    Keywords: Average velocity ; Fast GC ; High pressure drop ; Plate height ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Typically, fast GC requires high column pressure drop. Under that condition, known relations do not provide a complete description of dependence of [apparent] plate height, ĥ, on average velocity, u, of carrier gas.A complete descriptions for ĥ vs. u is derived and analyzed. It is shown that, under the high pressure drop, ĥ = B/u2 + C1 u2 + C2 u. This is substantially different from the Van Deemter equation ĥ = B/u + Cu for the low pressure drop. Analytical expressions for the minimum plate height and for the respective optimum u under the high pressure drop are derived and analyzed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240201106
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Theory of Fast Capillary Gas Chromatography Part 4: Column Performance vs.Liquid Film Thickness (1999)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 501-508 
    Details
    ISSN: 0935-6304
    Keywords: Fast GC ; film inefficiency factor ; high pressure drop ; thick film columns ; thin film columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The negative effect of the liquid stationary phase film thickness on the column efficiency is strongest for peaks with retention factors, k, in the vicinity of k = 0.3-0.4 and rapidly diminishes with the departure of k from that region. Additionally, at the high pressure drop required for fast analysis of complex mixtures, the negative effect of the same film thickness diminishes with the increase in column length, regardless of the k values. In practice, it is recommended to ignore the film thickness and optimize the columns as thin film ones regardless of their actual film thickness. Accounting for the film thickness results only in a modest improvement in the resolution for a few affected peaks - those with k = 0.3-0.4. However, this improvement comes at the cost of a substantial increase in analysis time, and should be used only as the action of the last resort.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Theory of fast capillary gas chromatography part. 2: Speed of analysis (1997)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 679-687 
    Details
    ISSN: 0935-6304
    Keywords: Efficiency-optimized column ; Efficiency-optimized gas velocity ; Fast GC ; High pressure drop ; Speed of analysis ; Speed-optimized column ; Speed-optimized gas velocity ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using hold-up time as a measure of the speed of analysis with a given column efficiency, a theory of pneumatic optimization of a column in the fast high pressure drop isothermal and temperature programmed GC is developed. Expression for the hold-up time as a function of column efficiency, carrier gas velocity and film thickness is derived. Also found are the expressions for the minimum hold-up time and optimum gas velocity in a speed-optimized column. These quantities are compared with their counterparts in the efficiency-optimized column.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240201212
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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