Studying the Sorption of Certain Benzimidazoles on Octadecyl Silica Gel from Water–Acetonitrile Solutions via Liquid Chromatography

Abstract

The effect the composition of a water–acetonitrile eluent has on the sorption of benzimidazoles by octadecyl silica gel is studied using the Snyder–Soczewinski model. Three-parameter equations associating retention factors and certain physicochemical characteristic of the molecules of benzimidazoles are obtained via linear regression analysis. Standard changes in the enthalpy of the transfer of benzimidazoles from the water–acetonitrile phase to the layer of octadecyl silica gel and entropic components of the process are calculated from the temperature dependences of the retention factors. The enthalpy–entropy dependences of sorption are discussed.