Effect of the Concentration of an Organic Modifier in a Water–Ethanol Mobile Phase on the Retention and Thermodynamics of Adsorption of Enantiomers of Hydroxy Acids and Their Derivatives on a Chiral Adsorbent with a Grafted Antibiotic Eremomycin

Abstract

Patterns of the retention and the thermodynamics of adsorption of enantiomers of aromatic hydroxy acids and their derivatives on a chiral stationary phase with a grafted macrocyclic antibiotic eremomycin from water–ethanol eluents under the conditions of linear liquid chromatography are studied. Dependences of the characteristics of retention, separation, and thermodynamic quantities on the concentration of the organic modifier in the eluent are found. The relationship between the structure of the investigated adsorbates and the retention and selectivity of the separation of their enantiomers is shown. It is demonstrated how extrathermodynamic correlations can be used to obtain information on the mechanism of adsorption. The difference between the mechanisms of adsorption of the enantiomers of hydroxy acids and their esters, and by hydroxy acids with a reverse order of elution of the (S)- and (R)-enantiomers, is found.