POLYETHYLENE-COATED SILICA AND ZIRCONIA STATIONARY PHASES IN VIEW OF QUANTITATIVE STRUCTURE-RETENTION RELATIONSHIPS

Retention properties of two new high-performance liquid chromatographi c (HPLC) stationary phases, polyethylene-coated silica (PECSiO(2)) and polyethylene-coated zirconia (PECZrO(2)), were compared chemometrical ly. Reversed phase HPLC capacity factors were determined isocratically for a carefully designed series of 25 structurally diverse solutes. L inear free energy relationship (LFER)-based solute parameters (excess molar refraction, dipolarity-polarizability, hydrogen-bond acidity and basicity, McGowan volume) and solute structural descriptors determine d by physico-chemical methods (water accessible van der Waals volume, dipole moment, atomic electron excess charge) were regressed as indepe ndent variables against log capacity factors. The quantitative structu re-retention relationships (QSRK) obtained show the predominating part ition mechanism of separation on both phases. Both the LFER parameters and the structural parameters obtained by molecular modelling produce d QSRR equations of high and practically identical retention predictio n ability. It has been concluded that intermolecular interactions of t he dipolarity-polarizability type manifest themselves more strongly on the silica-based phase than on the zirconia-based one. This can be du e to a role of active free silanols on the silica support.