Synthesis and characterization of polymer-coated mixed-functional stationary phases with several different hydrophobic groups for direct analysis of biological samples by liquid chromatography.

Three types of polymer-coated mixed-functional (PCMF) silica column-packing materials for the direct analysis of biological liquids have been synthesized. These packing materials all have polyoxyethylene groups as their hydrophilic part but differ in their hydrophobic part (methyl groups for Me-POE, phenyl groups for Ph-POE, and octyl groups for Oc-POE). Retention characteristics with respect to several drug molecules, and protein recovery, were studied for each of the three types with different amounts of hydrophobic groups attached. Of the PCMFs prepared, Oc-POE showed the greatest overall retention, and Me-POE displayed the greatest protein recovery.