UNIFORMLY SIZED POLY(VINYLPHENOL) POROUS BEADS - A VERSATILE HPLC SEPARATION MEDIUM ALLOWING FAST SWITCHING BETWEEN SIZE-EXCLUSION, NORMAL-PHASE, AND REVERSED-PHASE CHROMATOGRAPHY

Uniformly sized, 10 mu m porous 4-tert-butoxycarbonyloxystyrene-co-div inylbenzene) beads with controlled porosity were prepared by polymeriz ation of uniform size droplets consisting of small polymeric particles that were used as shape templates and enlarged with monomers and poro gens. The tert-butoxycarbonyl groups were removed by a thermal treatme nt that affords the desired poly(4-hydroxystyrene-co-divinylbenzene) s eparation medium. The pore size of the beads does not change when imme rsed in THF as the beads are additionally crosslinked upon heating in the deprotection step. The beads were tested in size-exclusion, normal phase, and reversed phase chromatography. The size-exclusion calibrat ion curve is almost linear in the range of molecular weights from 100 to about 480 000. Columns packed with the polymeric phenol beads can b e switched between normal and reversed-phase chromatography simply by changing the solvent without removing from the chromatograph and their chromatographic properties do not change even after several hundred i njections in different chromatographic modes including also multiple w ashing with aqueous sodium hydroxide. The retentions in separations of series of homologous alkylbenzenes, N-substituted, and ring substitut ed anilines were found to be linear functions of the number of carbon atoms, while interactions with the phenolic hydroxyls increased the re tention times of N-alkylanilines. Separation of a protein mixture usin g a column packed with the beads has also been demonstrated and very h igh protein recoveries have been obtained.