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  • 1995-1999  (3)
  • Supercritical fluid chromatography  (2)
  • Effect of pH and column temperature  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 47 (1998), S. 189-196 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Experimental design ; Mosapride ; Reversal of retention order ; Effect of pH and column temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Enantiomeric separation of mosapride and a structurally related compound was performed using chiral chromatography and experimental design. Unique effects of mobile phase pH and column temperature made it possible to control the elution order of the enantiomers when using Chiral-AGP as the solid phase. At a low mobile phase pH (〈6) the (R)-enantiomer of mosapride elutes before the (S)-form whereas the (S)-enantiomer elutes first at a high mobile phase pH (〉6). By using a mobile phase pH around 6, the column temperature could also be used to control the elution order of the enantiomers of mosapride. Similar effects of mobile phase pH and column temperature were obtained for the enantiomers of a structurally related compound, a metabolite (M1). Isocratic chromatographic systems made it possible to determine enantiomeric impurities less than 0.1% in the respective enantiomer of mosapride. The enantiomers of mosapride as well as the enantiomers of M1 could easily be separated simultaneously using Chiral-AGP and a simple gradient elution.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 49 (1999), S. 327-332 
    ISSN: 1612-1112
    Schlagwort(e): Supercritical fluid chromatography ; Semi-preparative chromatography ; Peak compression effect ; Dihydropyridine drug
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Peak compression of a dihydropyridine drug, clevidipine, is obtained in both analytical and semi-preparative scale supercritical fluid chromatography, resulting in extremely high apparent efficiencies. The observed effect, when utilising a carbon dioxide/2-propanol mobile phase with a bare silica stationary phase, is achieved when the retention of the clevidipine peak is controlled to coalesce with a system peak, generated as a result of having water in the sample. Apparent efficiencies of 350,000 and 170,000 plates meter−1 were obtained when 0.25 and 0.5 mg, respectively, are directly injected to a 200×4.6 mm ID 5 μm Hypersil silica packed column. The effect was extended to a semi-preparative system where apparent efficiencies in the region of 2,000,000 plates meter−1 were observed when 0.3 mg of a clevidipine sample containing 80% water was injected to a 250×10 mm I.D. column containing 5-μm Hypersil silica particles.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1612-1112
    Schlagwort(e): Supercritical fluid chromatography ; Peak compression ; Chemometrics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary In this paper chemometrics have been used to study and characterize peak compression phenomena in packed column SFC. A carbon dioxide/2-methyl-1-propanol mobile phase was used in the experimental design (modifier concentration, temperature and pressure) and modelling part of the investigation. A cubic interaction term was needed in the model to obtain a reasonable fit, suggesting that all three parameters are of significance in terms of controlling peak compression. At the optimum conditions derived from the model a narrow peak was obtained as predicted.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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