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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 8 (1985), S. 718-726 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns, glass ; Inert, stable stationary phases ; Leaching ; Immobilization by condensation ; OH terminal groups ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Coating intensively leached silica surfaces with OH-terminated phases provides a new way of producing, by simple means, columns with substantially increased inertness and thermostability. In addition, their separation efficiency is found to be typically higher than that of columns with traditional coatings. The underlying basic effect is a condensation process between terminal silanol groups of the phase and residual silanols, of the glass surface, thus producing the mentioned inertness. Moreover, the surface-bonded molecules are immobilized without addition of a radical generator. If required, crosslinking can also be effected using a volatile azo compound. No vinyl groups are required for this additional immobilization process. The paper discusses all processes involved, and gives detailed working directions for the following medium polar phases. OV-1701-OH, OV-31-OH (new, 17% cyanopropyl), OV-61-OH, and OV-17-OH, and the apolar phases PS-347.5 and PS-086. There is no doubt so far that the principle of terminal silanol groups is applicable to all silicone phases, and may replace the traditional endcapped stationary phases in the future.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns, glass ; Polyalkyleneglycol ether phases ; Inert columns ; Immobilization by condensation ; Methyltrimethoxysilane, coupling agent ; Trifluoroacetic acid, catalyst ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using UCON 50 HB-5100, one of the most successful stationary phases in capillary gas chromatography during the past decade, as an example, we wish to redirect attention to the excellent properties of the polyethylene/polypropyleneglycol ether copolymer coatings. Based on experience gained in work with OH-terminated polysiloxanes, a method is described for preparing inert and relatively temperature stable chemically bonded and crosslinked coatings in a single working step. Methyltrimethoxysilane was used as coupling agent, and trifluoroacetic acid was introduced as an acidic catalyst. The reaction mechanisms involved as well as the influence of additional crosslinking on the column behavior are discussed, particularly with respect of the inertness of the coatings.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Capillary columns, glass ; OV-240-H, 33% cyanopropyl ; Immobilization by condensation ; Crosslinker, dimethyltetramethoxysiloxane ; in situ methylation, diazomethane ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Coating intensely leached glass capillaries with OV-240-OH, the most polar commercially available OH-terminated polysiloxane phase at the present time, is described. Beside chemical bonding of the phase via condensation with silanol groups of the support, additional immobilization using dimethyltetramethoxysiloxane as a crosslinker is carried out. After in situ methylation of the immobilized coating, and transformation of acidic impurities of the cyanopropyl substituted phase into the respective methyl esters, increased inertness of the column was observed. Working instructions are given, and processes involved are discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 10 (1987), S. 472-476 
    ISSN: 0935-6304
    Keywords: Gas chromatography, high temperature ; Capillary columns, glass ; OH-terminated polysiloxane, PS-089 ; Immobilization by condensation ; Crosslinker, methyltrimethoxysilane ; Analysis of antioxidants and UV-stabilizers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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