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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 8 (1985), S. 395-400 
    ISSN: 0935-6304
    Keywords: Multidimensional gas chromatography, GC ; Capillary columns ; Electron capture detection ; Flame ionization detection ; Double oven instrument ; Kovats indices ; Halogenated aromatic hydrocarbons ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A multidimensional GC-system containing two capillary columns of different polarities, operated within a double oven instrument, was used for the optimized separation of complex isomeric mixtures of various types of chlorinated aromatic compounds such as PCB, PCDD, or PCDF. Electron capture was applied parallel to flame ionization detection to obtain sensitive signals of the PCB or PCDD and the n-alkane standards required for identification by Kovats indices, respectively. Electron capture detection within a valvelessly operated MDGC system forced changes in the usual instrumental set-up, the live-switching coupling piece being located within the second oven of the double oven instrument. This oven is operated isothermally to ensure optimal and interference-free detection, for stable flow conditions within the coupling piece and for the determination of the isothermal retention indices (Kovats), which are much more suitable for identification by retention than the so-called “linear” indices.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 8 (1985), S. 566-571 
    ISSN: 0935-6304
    Keywords: Gas chromatography, GC ; Capillary columns ; Cooled needle split injection ; Temperature programmed (PTV) injection ; On-column injection ; Automation ; Quantitation ; Sampling ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sampling techniques for practical quantitative capillary GC have to meet certain principal requirements. Both the absolute and the relative peak areas (e.g. column loads) must be reproducible with high precision and at high accuracy; discrimination of certain constituents according to their volatility should not take place on sampling. On the basis of systematic studies, the three most reliable sampling techniques used for GC analyses with the aim of achieving precise and accurate quantitative data proved to be the following: On-column, injection, splitless PTV injection, and an optimized version of split sampling called “cooled needle split” injection. The on-column technique can be optimized by using precolumns with wider internal diameters and without stationary phase coatings to overcome the problems of large liquid sampling volumes and for automation. The PTV technique should only be used in the splitless mode because discrimination cannot be suppressed completely with the split mode. All three of the techniques can be operated automatically, either to avoid “human interference”, i.e. to improve precision or for unattended operation to save man-power.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Immobilized capillary columns ; Aqueous solutions ; On-column injection ; Split injection ; Multidimensional separations ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Various methods of gas chromatographic analysis at high resolution and low detection limits in aqueous solutions are described with regard to sampling techniques, column technology, and the application of coupled pre-columns, also including multidimensional methods. Immobilized polyethylene glycol (Carbowax 20 M) columns have also been produced and used successfully.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 206-207 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 5 (1982), S. 565-567 
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Quantitation ; On-column injection with splitting and splitless sampling ; Pre-column ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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