CHEMICALLY BONDED PHENYLSILICONE STATIONARY PHASES FOR THE LIQUID CHROMATOGRAPHIC SEPARATION OF POLYCYCLIC AROMATIC HYDROCARBONS AND CYCLOSILOXANES

摘要

Chemically bonded phenylsilicone stationary phases, prepared from polymethylphenylsiloxane (PMPS) bonded silica gel, have been developed for use in high-performance liquid chromatography (HPLC) to separate compounds containing aryl groups through pi-pi interaction. Silanol-terminated PMPS was synthesized through living anionic polymerization of methylphenylcyclotrisiloxane. The PMPS bonded phases, with different degrees of polymerization (DP), were prepared by bonding silanol-terminated PMPS directly onto silica gel. The stationary phases thus prepared were characterized by elemental analysis, gel permeation chromatography, IR, H-1 NMR and Si-29 NMR. Evaluation of their chromatographic behavior in relation to small PAHs (polycyclic aromatic hydrocarbons) and various cyclosiloxanes showed them to have reasonable separation ability in both normal-phase and reversed-phase. Copolymerization reactions of trifluoropropylmethylcyclotrisilioxane (F-3) and hexaphenylcyclotrisiloxane (P-3) were followed on these stationary phases, and their performance in the retention of phenyl-containing siloxane copolymers with different compositions was also evaluated. Comparison of these PMPS phases with a commercial ODS (C-18) phase in analyses of PAHs and cyclosiloxanes indicates clearly the significant contribution made by the phenyl moiety on the siloxane backbone to the pi-pi interaction in the HPLC separation process.