CHARACTERIZATION OF POLYBUTADIENE-COATED ZIRCONIA AND COMPARISON TO CONVENTIONAL BONDED PHASES BY USE OF LINEAR SOLVATION ENERGY RELATIONSHIPS

This paper describes the use of linear solvation energy relationships (LSERs) to thermodynamically characterize retention on a reversed-phas e type material based on polybutadiene (PBD)-coated zirconia. Retentio n data were obtained for a large set of judiciously selected test solu tes on four PBD phases (carbon loads varying from 1.5 to 5.6% by weigh t) in various methanol-water mobile phases. Based on the LSERs, the fr ee energy of retention was dissected into contributions from cavity fo rmation/dispersive interactions, dipolar interactions, and hydrogen bo nd (HE) donor-acceptor interactions, The PBD-zirconia phases were comp ared to conventional silica-based bonded reversed phases. As is the ca se with conventional bonded phases, the solute's size and HE acceptor basicity are the predominant retention determining factors, and on the whole, PBD-zirconia phases closely resemble conventional chemically b onded reversed phase materials. Interestingly, the solute's basicity h as a larger effect on its retention on the PBD-zirconia phase than on conventional bonded phases, so relative to their behavior on conventio nal phases, strong hydrogen bases and highly dipolar analytes, when co mpared to nonpolar solutes, are less strongly retained on PBD-zirconia than on conventional phases. PBD-zirconia and conventional phases are so similar that there should be little difficulty in transferring sep aration methods between phases.