Effect of the partial molar volume of the solute in the stationary phase on retention in supercritical fluid chromatography

Abstract

Retention in supercritical fluid chromatography is a dynamic mechanism, involving intermolecular interactions in the mobile and stationary phases. A simple thermodynamic model, describing solute retention, has been investigated on the basis of macroscopic thermodynamic variables of the solute partial molar volume in the stationary and mobile phases. Solute-solvent interactions in the mobile phase are dominant at lower pressures. Solute-stationary phase interactions have an important role in solute retention in capillary supercritical fluid chromatography. The interaction of the solute with the five different stationary phases reflects the polarizability differences between these phases, as shown by the partial molar volume of the solute in the stationary phase.