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  • Electronic Resource  (2)
  • 1990-1994  (2)
  • Electronic interactions  (1)
  • Nonylphenyl ethylene oxide oligomers  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Retention of some ring-substituted aniline derivatives by porous graphitized carbon. Dependence on physico-chemical parameters (1992)
    Springer
    Chromatographia 33 (1992), S. 356-360 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Porous graphitized carbon ; Ring-substituted aniline derivatives ; Electronic interactions ; Principal component analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention characteristics of 22 aniline derivatives were determined on a porous, graphitized-carbon column in unbuffered acetonitrile-water and methanol-water mixtures. Each aniline derivative gave symmetrical peaks in each eluent without buffers. Good linear correlations were found between the log k′ and the concentration of the organic component in the eluent. The slope and intercept values differed according to the type of organic modifier and the charcter, number and position of substituents, indicating the different selectivities of methanol and acetonitrile and the good separating power of the column. Multivariate mathematical-statistical calculations proved that the retention of ring-substituted aniline derivatives is mainly governed by electronic parameters and the hydrogen acceptor capacity of substituents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02275918
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of nature of support and impregnating agent on lipophilicity determination for nonionic surfactants by reversed-phase thin-layer chromatography (1991)
    Springer
    Chromatographia 31 (1991), S. 152-156 
    Details
    ISSN: 1612-1112
    Keywords: Thin-layer chromatography ; Nonylphenyl ethylene oxide oligomers ; Lipophilic solid phases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention of 9 nonylphenyl ethylene oxide oligomers was determined in 15 reversed-phase chromatographic systems using silicone oils of various molecular mass as impregnating agents and silica, cellulose and alumina supports. The data were evaluated with principal component analysis carried out on the covariance and the correlation matrices. The RM values did not follow the additivity rule and they did not change linearly with increasing length of the ethylene oxide chain. This is probably due to the folded state of the chain in the eluent. The molecular mass of the silicone oils had a negligible effect on the retention whereas the retention increased with increasing level of impregnation. The support considerably influenced the lipophilicity values of these nonionic surfactants and cellulose seemed to be the most appropriate support. Calculations proved that the application of a correlation matrix may cause data distortion; therefore, the use of a covariance matrix is strongly proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02274564
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    Paper (German National Licenses)
    Fulltext
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