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  • 1
    Electronic Resource
    Electronic Resource
    The preparation of non-extractable methylphenylpolysiloxane stationary phases for capillary column gas chromatography (1982)
    Springer
    Chromatographia 15 (1982), S. 335-340 
    Details
    ISSN: 1612-1112
    Keywords: Capillary gas chromatography ; Fused silica capillary columns ; Crosslinked phenyl polysiloxanes ; Non-extractable stationary phases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The synthesis of methylphenylpolysiloxane polymers and their use in the preparation of crosslinked, non-extractable stationary phases for fused-silica capillary columns are described. By preparing more viscous phenyl-containing polymers than are commercially available, stationary phase films of these polymers could be efficiently coated on fused-silica capillary columns and stabilized by a free radical crosslinking mechanism using peroxides. Four methylphenylpolysiloxane polymers containing different phenyl concentrations were prepared. These included three polymers containing 50% phenyl and one polymer containing 70% phenyl. Two of the 50% phenyl polymers had one phenyl and one methyl group attached to each silicon atom. One of these also had 1% vinyl incorporated. The third 50% phenyl polymer was synthesized in such a way that one half of the silicon atoms had two phenyl groups attached while the rest contained dimethyl groups. The 70% phenyl polymer also had 4% vinyl incorporated. Due to the intrinsic thermal stability of these phenyl phases and the enhanced film stability achieved by crosslinking, the 70% phenyl phase could be utilized up to 400 °C. Using the methods described in this paper, highly efficient and thermally stable fused silica capillary columns coated with crosslinked methylphenylpolysiloxane stationary phases can be successfully prepared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02259213
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  • 2
    Electronic Resource
    Electronic Resource
    Characterization of glass, quartz, and fused silica capillary column surfaces from contact-angle measurements (1981)
    Springer
    Chromatographia 14 (1981), S. 387-397 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Capillary columns ; Fused silica ; Contact angle ; Wettability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This paper describes the systematic characterization of glass and the newly introduced fused silica and quartz capillary columns from surface wettability measurements. Common gas chromatographic stationary phases were used in capillary-rise measurements at temperatures up to 300°C. By construction of Zisman plots and using the Cassie equation, the relative surface concentrations of wettable and non-wettable groups were determined. By application of the Fowkes equation, the dispersion force component of the surface energy was investigated. The influence of various surface treatments such as leaching, silylation, and polymeric film formation are discussed. Wettability measurements were also used to evaluate the thermostability of various treated surfaces and to compare the surface properties of glass, quartz, and fused silica. The wettability of the surfaces with selected stationary phases as a function of temperature is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02262872
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  • 3
    Electronic Resource
    Electronic Resource
    Factors affecting the retention of polycyclic aromatic hydrocarbons in gas chromatography (1981)
    Springer
    Chromatographia 14 (1981), S. 69-72 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Polynuclear aromatic hydrocarbons ; Retention index ; Vapour pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention index of a planar polynuclear aromatic hydrocarbon on the GC phases OV-101, SE-52, and OV-17 is strictly related only to the boiling point, and less closely to the relative molecular mass. The very approximates relation with connectivity index ins only a consequence of the latter. On a nematic lqiuid crystal phase, a variation of activity coefficient, expressed in terms of a shape factor, also influences the retention of PAH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279514
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  • 4
    Electronic Resource
    Electronic Resource
    CRC handbook of chromatography carbohydrates volume 1 (1982)
    Springer
    Chromatographia 15 (1982), S. 378-378 
    Details
    ISSN: 1612-1112
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02259224
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  • 5
    Electronic Resource
    Electronic Resource
    Nonextractable cyanopropyl polysiloxane stationary phases for capillary chromatography (1983)
    Springer
    Chromatographia 17 (1983), S. 570-573 
    Details
    ISSN: 1612-1112
    Keywords: Cyanopropyl polysiloxane ; Stationary phase ; Capillary chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Crosslinkable cyanopropylpolysiloxane stationary phases have been difficult to produce because of steric effects of the large cyanopropyl groups or because of the interaction between the polar cyanopropyl groups and the groups added for crosslinking. Various polymers containing 50% to 90% cyanopropyl were synthesized which contained vinyl,p-tolyl, or 4-vinylphenyl groups for crosslinking. Thep-tolyl group was found to give satisfactory crosslinking if there were two such groups attached to one silicon atom.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02261921
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  • 6
    Electronic Resource
    Electronic Resource
    Static coating of capillary columns using mixed solvents (1983)
    Springer
    Chromatographia 17 (1983), S. 451-453 
    Details
    ISSN: 1612-1112
    Keywords: Static coating ; Mixed solvents ; Capillary gas chromatography ; Capillary supercritical fluid chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Mixed solvents in coating solutions were employed to facilitate (lower temperatures and shorter times) the static coating of capillary columns. Different volume ratios of mixed solvents used in the coating solutions do not affect the quality of capillary columns coated with stationary phases of different polarity. Small diameter (〈100 μm i.d.) capillaries of up to 50 m long were successfully coated with a methylphenylpolysiloxane (50% phenyl) for use in supercritical-fluid chromatography. In addition, an 80 m×0.31 mm i.d. capillary was statically coated with Superox 20 M (0.25 μm film thickness) in a 1∶1n-pentane/methylene chloride mixture at 55 °C. The coating time was only 7 hrs, and the resultant column exhibited a total of 170,000 theoretical plates (k′=5.5).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02262929
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  • 7
    Electronic Resource
    Electronic Resource
    Deactivation of small-diameter fused-silica capillary columns for gas and supercritical fluid chromatography (1984)
    Springer
    Chromatographia 18 (1984), S. 362-366 
    Details
    ISSN: 1612-1112
    Keywords: Deactivation of columns ; Capillary gas chromatography ; Capillary supercritical fluid chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In order to prevent plugging during deactivation of small diameter (50 μm i.d.) capillary columns for gas and supercritical fluid chromatography, various high temperature deactivation methods were employed. Pure hexamethyldisilazane and hexamethyldisiloxane (a substitute for D4) were dynamically coated on the column, while a film (0.05 μm) of OV-101 was statically coated, before high temperature (450°C) treatment. Excellent deactivated columns were obtained, and no significant difference in column activity was observed using any of these three methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02262481
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  • 8
    Electronic Resource
    Electronic Resource
    Determination of surface hydroxyl concentration on glass and fused silica capillary columns (1982)
    Springer
    Chromatographia 15 (1982), S. 584-586 
    Details
    ISSN: 1612-1112
    Keywords: Surface hydroxyl quantification ; Siliceous capillary columns ; Capillary gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The concentration of surface hydroxyl groups on three types of capillary columns was determined by exchanging the hydroxyl protons with tritium. The tritium was quantified by combustion to tritiated water followed by scintillation counting. The number of hydroxyl groups on a leached and presumably hydroxylated Pyrex glass capillary column was found to be about 2.8 groups per square nanometer. This value was slightly less than the 4.6 groups per square nanometer that is generally accepted for a fully hydroxylated porous silica. Dehydroxylation of the same glass by heating at 600°C left only 0.4 groups per square nanometer while an untreated fused silica had only 0.2 groups per square nanometer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02280379
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  • 9
    Electronic Resource
    Electronic Resource
    CRC handbook of chromatography carbohydrates, volume 1 (1983)
    Springer
    Chromatographia 17 (1983), S. 230-230 
    Details
    ISSN: 1612-1112
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290563
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  • 10
    Electronic Resource
    Electronic Resource
    Trace element analysis of maternal scalp hair by external beam proton-induced X-ray emission (PIXE) (1984)
    Springer
    Journal of radioanalytical and nuclear chemistry 82 (1984), S. 329-339 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We have constructed an external beam proton-induced X-ray emission (PIXE) system for trace element analysis of biological and environmental samples. Optimization of sample preparation and experimental PIXE set up has produced a rapid, accurate, sensitive, and reliable PIXE analysis procedure. The analytical procedure was evaluated using maternal scalp hair from pregnant women 16–19 weeks' gestation. The samples were irradiated with 3.5 MeV protons from the Rutgers Nuclear Physics Department's 8 MV Tandem FN Van de Graaff accelerator. The concentrations of the elements calcium (Ca) to cadmium (Cd) in hair are reported for 50 subjects. The analytical procedure is suitable for non-invasive clinical analysis for evaluation of nutritional states and for environmental exposure to toxic metals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02037055
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