PREPARATION AND CHROMATOGRAPHIC PROPERTIES OF UNIFORM SIZE CROSS-LINKED MACROPOROUS POLY(VINYL P-TERT-BUTYLBENZOATE) BEADS - EVALUATION OF PREFERENTIAL RETENTION TOWARD ORGANOHALIDES

Uniform size cross-linked macroporous poly(vinyl p-tert.-butyl benzoate) beads (VPTBBA) were prepared by a two-step swelling and polymerization method. VPTBBA was obtained in 78% yield and utilized as a packing material in high-performance liquid chromatography. The specific surface area of VPTBBA, which had a polymodal broad pore size distribution, was calculated as 314 m(2)/g by the BET method. In the reversed-phase mode, VPTBBA showed preferential retention towards some aromatic and/or aliphatic halogenated compounds. In a comparison of its chromatographic properties with those on other packing materials such as two kinds of poly(vinyl carboxylate)-based beads, poly(styrene-divinylbenzene) beads and poly(methyl methacrylate-ethylene dimethacrylate) beads, and a silica-based monomeric C-18 stationary phase, the selectivities on VPTBBA can be explained mainly based on both dipole-dipole interactions caused by the pi-acidic phenyl group of VPTBBA and preferential retention towards planer solutes. Moreover, the relatively hydrophobic tert.-butyl groups contribute to steric selectivity and to the total hydrophobicity of the packing material.