Experimental results for the separation of R,S-omeprazole enantiomers obtained on preparative columns packed with amylose tris(3,5-dimethylphenylcarbamate) chiral stationary phase are presented. The total porosity was measured by using the non-retained compound 1,3,5-Tri-tert-butylbenzene. The efficiency of columns was characterized by the height equivalent to a theoretical plate (HETP) and a linear dependency has been found over tested flow rates. The HETP dependence on the mobile phase was determined to acquire the equilibrium and kinetics data of adsorption of racemic mixture of omeprazole. The retention factors and selectivity factors for the enantiomers of the omeprazole decreased with increasing temperature. The natural logarithms of the retention factors (ln k) depended linearly on the inverse of temperature (1/T). van’t Hoff plots afforded thermodynamic parameters, such as the apparent change in enthalpy (ΔH0) and the apparent change in entropy (ΔS0) for the transfer of analyte from the mobile to the stationary phase. Thermodynamic adsorption parameters (ΔH0 and ΔS0) were calculated in order to promote an understanding of the driving forces for retention in this chromatographic system. Frontal analysis method was applied for the determination of the adsorption isotherms for the enantiomers of omeprazole. The isotherms, for both enantiomers, were adjusted satisfactorily to the Langmuir model.
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