A NOVEL POLAR SEPARATION MEDIUM FOR THE SIZE-EXCLUSION CHROMATOGRAPHYOF SMALL MOLECULES - UNIFORMLY SIZED, POROUS POLY(VINYLPHENOL-CO-DIVINYLBENZENE) BEADS

A novel separation medium based on uniform size beads of 4-hydroxystyr ene-divinylbenzene call be used for both the size exclusion chromatogr aphy of small molecules and their separation by reversed-phase chromat ography. The new 5 mu m material is prepared by the controlled swellin g of monodispersed polystyrene particles, that serve both as porogen a nd shape template, with a polymerization mixture consisting of the mon omers and dibutylphthalate,followed by a suspension polymerization. Re moval of the acetoxy groups by hydrolysis with aqueous base leads to t he final poly(4-vinylphenol-co-divinylbenzene) monodispersed beads. Po lymerization conditions that favor the formation of very small pores w ere developed to optimize-the beads for the SEC separation of small mo lecules. The SEC calibration curve confirms that the optimized beads c ontain a large volume of pores suitable for the separation of solutes with a molecular weight of up to about 1000. The ability to separate a lkylbenzenes according to their hydrodynamic sizes has been demonstrat ed using a column packed with this material. In addition, the phenol c hemistry used in combination with a hydrophobic crosslinking monomer p rovides this separation medium with an unusual versatility that allows both reversed phase and normal phase chromatography to be run in the same column after a simple change of the mobile phase.