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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Microchimica acta 102 (1990), S. 35-53 
    ISSN: 1436-5073
    Schlagwort(e): ion-pair chromatography ; Freundlich isotherm ; retention equation ; statistical thermodynamic method
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In this paper, by combination of the statistical thermodynamic method with the Freundlich isotherm, the retention equations to describe the effects of the mobile phase composition, concentration of the ion-pair reagent and the ionic strength on the amount of adsorbed ion-pair reagent and the retention value of the ionic solute have been reported by simultaneously considering the electrostatic and molecular interaction between solutes, ion-pair reagent and molecule or ion in each phase in the reversed-phase ion-pair chromatography. The validity of these retention equations has been confirmed by calculation of capacity factor of the different phenylamine and naphthylamine sulphonic acids during systematic change of concentration of the strong solvent, the ion-pair reagent and the ionic strength in the mobile phase.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 23 (2000), S. 67-72 
    ISSN: 0935-6304
    Schlagwort(e): Capillary electrochromatography ; monolithic column ; electroosmotic flow ; retention mechanism ; aromatic compound ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A new kind of monolithic capillary electrochromatography column with poly(styrene-co-divinylbenzene-co-methacrylic acid) as the stationary phase has been developed. The stationary phase was found to be porous by scanning electron microscopy and the composition of the continuous bed was proved by IR spectroscopy to be the ternary polymer of styrene, divinylbenzene, and methacrylic acid. The effects of operating parameters, such as voltage, electrolyte, and organic modifier concentration in the mobile phase on electroosmotic flow were studied systematically. The retention mechanism of neutral solutes on such a column proved to be similar to that of reversed-phase high performance liquid chromatography. In addition, fast analyses of phenols, chlorobenzenes, anilines, isomeric compounds of phenylenediamine and alkylbenzenes within 4.5 min were achieved.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 22 (1999), S. 666-670 
    ISSN: 0935-6304
    Schlagwort(e): Capillary electrochromatography ; mixed packing technique ; electroosmotic flow ; retention mechanism ; fast analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Mixed packing capillary electrochromatography (MP CEC) with the stationary phase comprising a physical mixture of strong cation exchange (SCX) phase and octadecysilyl (ODS) phase was developed. With the existence of a sulfonic acid group on the surface of SCX, not only could the electroosmotic flow (EOF) remain high at low pH, but also the hydrophilicity of the stationary phase was increased greatly, leading to broad adaptable ranges of both pH and organic modifier concentration in the mobile phase. At the same time, with the coexistence of C18 on the surface of ODS, both the retention and the resolution of samples were improved. Accordingly, MP CEC combined the advantages of both SCX and ODS columns. Effects of operation parameters on EOF and the capacity factors of solutes as well as the retention mechanism of such a column were studied systematically. In addition, MP CEC columns were used in the analysis of strong polar solutes as well as for the high speed separation of acidic, basic, and neutral compounds in a single run.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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