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  • Articles  (4)
  • Macroporous silica  (2)
  • Relationship between retention and molecular structure  (2)
  • Springer  (4)
  • 1
    ISSN: 1612-1112
    Keywords: High-performance liquid chromatography ; Cyano-silica stationary phases ; Polycyclic aromatic compounds ; Relationship between retention and molecular structure ; Retention mechanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The paper discusses the effect of the length and structure of the hydrocarbon chain connecting the nitrile group to the silica gel surface on the chromatographic properties of cyanoalkyl phases. When using non-polar and polar mobile phases, the selectivity of the cyanodecyl phases toward PAHs is higher than of the cyanopropyl phase and of hydroxylated silica gel. Polar additives to the mobile phase drastically decrease the retention on silica gel and on the cyanopropyl phase while affect the properties of cyanodecyl phases only to a considerably less degree. Newly synthesized phases with different structures of the hydrocarbon chain are compared with the commerical cyano-and ODS-phases. The retention mechanism on the cyanoalkyl phases is discussed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1612-1112
    Keywords: Liquid chromatography ; Polyaromatic hydrocarbons ; Polar stationary phase ; Relationship between retention and molecular structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention of polynuclear aromatic hydrocarbons (PAH) is studied in liquid chromatography, using columns packed with silica gel with a hydroxylated surface and the same silica gel with surface-bonded amine and nitrile groups. A linear relationship was found between retention and the number of π-electrons in the molecule, the size of the molecule and the different types of carbon atoms in the molecule. The different carbon atoms in a PAH molecule contribute differently to the retention and this contribution depends on the nature of the polar functional groups on the adsorbent's surface and on the nature and concentration of a polar modifier present in a non-polar eluent.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Macroporous silica ; Silica-adsorbent modification ; Low boiling halocarbons ; Analysis of water pollutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of the silica adsorbent Silochrom C-80 modified by a thin liquid stationary phase film is proposed for the gas chromatographic analysis of low molecular weight halocarbons. Such modified adsorbents are characterized by good retention of the volatile halocarbons and high selectivity with respect to halocarbons. The thermodynamic sorption characteristics of alkanes, chloroalkanes and chloromethanes on Silochrom modified by three liquid phases (Apiezon L, methylsilicone and polyethylene glycol 20M) and on Chromaton N with thick films of the same phases were studied. The heats of sorption (−ΔH) and free sorption energy changes (−ΔF) of these substances and the increments −Δ(ΔH) and −Δ(ΔF) per chlorine atom in the chloralkane molecule compared with n-alkanes with the same number of carbon atoms were determined. The “chlorine” retention indices of low molecular weight volatile halocarbons on three sorbents were determined to identify them in aqueous solutions using the electron-capture detector. The analysis of drinking water by this technique is demonstrated.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 18 (1984), S. 69-72 
    ISSN: 1612-1112
    Keywords: Liquid column chromatography ; Proteins ; Viruses ; Macroporous silica ; Surface chemical modification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The adsorption and the chromatography of proteins and viruses on macroporoussilicas have been studied. Modification of the silica surfaces with γ-aminopropyltriethoxysilane and then with carbohydrates has eliminated the irreversible adsorption of these biopolymers. The chromatographic separation of the biopolymers has revealed molecular sieve (size exclusion) effects and reversible adsorption. The influence of pH on the elution of proteins and viruses has been demonstrated.
    Type of Medium: Electronic Resource
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