Quantitative retention-structure and retention-activity relationships of barbiturates by micellar liquid chromatography

Studies on the structural requirements of chromatographic surfaces to emulate in vitro the partitioning process in biomembranes are of great interest. The use of micellar mobile phases in RPLC modifies the hydrophobicity of the stationary phase and provides hydrophobic and electrostatic sites of interaction as a consequence of the adsorption of surfactant monomers to the chromatographic surface. Modified stationary phases in MLC could be structurally similar to biomembranes, but thorough studies are necessary to confirm this. In this paper we focus our attention on barbiturates. The influence of the nature and concentration of the surfactant (Brij 35, SDS and CTAB) and the mobile phase pH on the retention of 13 barbiturates in modified C-18 stationary phases is studied. Quantitative structure-retention and structure-activity relationships for the barbiturates with different surfactants are proposed and compared with those obtained using hydro-organic mobile phases. (C) 1998 Elsevier Science B.V. All rights reserved.