Nonporous beads having an average diameter of about 0.5-100 microns are suitable for chromatographic separation of mixtures of polynucleotides when the beads comprise a nonporous particle which are coated with a polymer or which have substantially all surface substrate groups endcapped with a non-polar...http://www.google.de/patents/US6056877?utm_source=gb-gplus-sharePatent US6056877 - Non-polar media for polynucleotide separations
