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  • 1
    Electronic Resource
    Electronic Resource
    Crosslinking of alkylpolysiloxane filsm on various types of glass surfaces including fused silica using γ-radiation of a60cobalt-source. Comparison to crosslinking by thermal peroxid treatment (1982)
    Springer
    Chromatographia 15 (1982), S. 599-610 
    Details
    ISSN: 1612-1112
    Keywords: Alkylpolysiloxanes ; Capillary columns ; Fused silica ; Soft glass ; Crosslinking by γ-radiation and peroxid treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Crosslinking of alkylpolysiloxane stationary phases, especially in thick film capillary columns, is useful for the homogenous coating of fused silica and pretreated alkaliglass surfaces. The films of the stationary liquid are immobilized against solvent rinsing using CH2Cl2, pentane, and acetone, and maintain homogenity even at high temperature. Various doses of γ-radiation from a60Co. source were used for the crosslinking instead of the thermal peroxid treatment recently described by other authors. The effect of the γ-radiation crosslinking-procedure was investigated in comparison to the peroxid method in regard of: decrease of stationary phase content by solvent rinsing, separation efficiency, tailing behaviour, and bleeding of the columns obtained. Similar results as with the cumylperoxid-treatment were achieved using the γ-radiation-method. By γ-radiation no polar functional groups or moleculs are introduced into the stationary phase, however, as with the peroxid method. Less than 20% of the various stationary liquids are usually removed from the columns by solvent rising after crosslinking using both methods depending on the doses of radiation and the cumylperoxid concentration applied respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02280382
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  • 2
    Electronic Resource
    Electronic Resource
    Multidimensional separation of isomeric species of chlorinated hydrocarbons such as PCB, PCDD, and PCDF (1985)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 8 (1985), S. 395-400 
    Details
    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
    URL: http://dx.doi.org/10.1002/jhrc.1240080807
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  • 3
    Electronic Resource
    Electronic Resource
    Quantitation in capillary gas chromatography with emphasis on the problems of sample introduction (1985)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 8 (1985), S. 566-571 
    Details
    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
    URL: http://dx.doi.org/10.1002/jhrc.1240080918
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    Paper (German National Licenses)
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