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  • 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
    Retention characteristics of an aluminium oxide HPLC column (1990)
    Springer
    Chromatographia 29 (1990), S. 593-596 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Alumina adsorbent ; Substituted anilines ; Retention data
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention of 29 aniline derivatives was determined by high performance liquid adsorption chromatography using an alumina column and dichloromethane-n-hexane mobile phases in various vol. ratios. The retention parameters of anilines (log k′ and the slope and intercept value of the correlation between log k′ and the dichloromethane concentration in the eluent) were correlated with the physicochemical parameters (lipophilicity and adsorption capacity of silica) of aniline derivatives. The retention of anilines decreased with their increasing lipophilicity and increased with their increasing silica adsorption capacity. The alumina columns was found to be an appropriate support for the adsorptive phase separation of polar compounds as aniline derivatives.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02261229
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Determination of the lipophilicity of some anti-hypoxia drugs: Comparison of TLC and HPLC methods (1993)
    Springer
    Chromatographia 35 (1993), S. 275-280 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thin-layer chromatography ; Anti-hypoxia drugs ; Lipophilic character and retention
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The lipophilicity of 14 anti-hypoxia drugs has been determined by reversed phase thin-layer (RPTLC) and reversed phase high performance liquid chromatography (RPHPLC) in eluent systems containing different concentrations of acetonitrile and potassium dihydrogen phosphate. There was significant correlation between lipophilicity and the specific hydrophobic surface area of the drugs in RPTLC, indicating that the drugs behave as an homologous series of compounds. In RPTLC the concentration of buffer has a negligible effect on the retention of the drugs whereas in RPHPLC the buffer concentration influenced the retention. This discrepancy can be explained by the lower sensitivity of RPTLC. There was strong correlation between lipophilicity values determined by both methods, proving that both are suitable for the determination of molecular lipophilicity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02277509
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Comparison of the retention behaviour of phenol derivatives on porous graphitized and octadecylsilica columns (1993)
    Springer
    Chromatographia 36 (1993), S. 19-26 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Structure-retention relationships ; Mathematical data analysis ; Phenol derivatives ; ODS and graphitized carbon columns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention of 22 ring-substituted phenol derivatives on porous graphitized carbon (PGC) (eluents: acetonitrile — water and methanol — water mixtures) and on octadecylsilica (ODS) (eluents: methanol — 0.025 M KH2PO4 mixtures) was determined, and the relationship between retention and physicochemical parameters were evaluated by principal component analysis followed by two-dimensional nonlinear mapping and by cluster analysis as well as by canonical correlation analysis. Calculations proved that marked differences can be detected between the retention characteristics of PGC and ODS columns, and the electronic parameters of phenol derivatives have the highest impact on their retention. The comparison of various multivariate mathematical-statistical methods indicated that principal component analysis followed by two dimensional non-linear mapping is the most appropriate method for the evaluation of large data matrices in RP-HPLC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02263830
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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