THE RELATIONSHIP BETWEEN SOLVENT EXTRACTION AND LIQUID CHROMATOGRAPHY (HPLC, STYRENE-DIVINYLBENZENE, COPOLYMER).

The use of a new styrene-divinylbenzene copolymer bead, Showdex Polymerpak D-814, as a stationary phase in high-performance liquid chromatography is investigated. Unlike conventional silica-based stationary phases, copolymer beads may be used with both aqueous and organic mobile phases. The effect of the mobile phase on solute retention with the copolymer beads is described. Although the copolymer beads exhibit characteristics of both solid and liquid stationary phases, it is shown that the beads act primarily as a liquid when used with the mobile phases chosen for this work. It is further shown that solute retention on the beads results from dispersion interactions between the solute and the stationary phase. Batch extraction distribution constants are determined to confirm the validity of the distribution model proposed. The chromatographic behavior of a variety of aromatic compounds is described. These range from polycyclic aromatic hydrocarbons to substituted benzenes to phthalate esters. A quantitative measure of the effect of a substituent group on retention is developed from an analysis of the experimental results. This measure is then used to successfully predict the retention behavior of some disubstituted benzene compounds. Some model separations are developed to illustrate the usefulness of this measure. Finally, the implications of this work for gradient elution chromatography are discussed