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Thermodynamic Approach to Enantioseparation of Aryl-Methyl Sulfoxides on Teicoplanin Aglycone Stationary Phase

Abstract Several structurally related aryl-methyl sulfoxides were chosen for a thermodynamic investigation of retention and enantioseparation on the teicoplanin aglycone chiral stationary phase in the normal phase mode. The temperature of the chromatographic column was controlled within the range of 10°C to 50°C. Van't Hoff plots showed linear dependencies between the logarithms of retention factors and reciprocal temperature. According to thermodynamic parameters (enthalpies and entropies of transfer) the enthalpy contribution seems to have a major influence on retention regardless of the structure of the studied sulfoxides. Enantioseparations of aryl-methyl sulfoxides using hexane/methanol (90/10 v/v) as the mobile phase were enthalpy driven. No coelutions of peaks or changes in the elution order were observed within the temperature range of this study. The measured value of the phase ratio can affect some parameters.