NOVEL UNIFORMLY SIZED POLYMERIC STATIONARY-PHASE WITH HYDROPHILIZED LARGE PORES FOR DIRECT-INJECTION HPLC DETERMINATION OF DRUGS IN BIOLOGICAL-FLUIDS

Novel separation media for the direct injection of complex samples hav e been prepared from porous 10 mu m uniformly sized poly(glycidyl meth acrylate-coethylene dimethacrylate) beads. The simple hydrolysis of al l epoxide groups produces beads with separation characteristics simila r to those of some restricted access media. The use of a novel size-sp ecific modification of porous materials provides separation media with even better chromatographic properties. In this approach, hydrolysis of the epoxide groups to diols can be carried out exclusively within t he large pores of the medium through the use of a polymeric catalyst. The epoxide groups remaining in the small pores after hydrophilization of the large pores were then transformed either to hydrophobic C-18 o r phenyl groups, or to more polar diethylamino groups. Due to the size specific characteristics of the modification process used in the prep aration of the beads which renders the large pores hydrophilic, no pro tein interaction with the surface of the pores was observed, the prote in recovery was high, and the retention times of proteins and of a non -retained probe was similar. Examples of separations of drugs from pla sma document the good efficiency and excellent selectivity of columns packed with the novel separation medium.