The use of porous, quaternized polyethylenimine-coated zirconia particles for the separation of nucleosides, nucleotides, oligonucleotides, and oligodeoxynucleotides is described. Separations of these biomolecules on quatemized PEI-zirconia are presented. Quaternized PEI-zirconia and a quaternary amine functionalized silica are compared chromatographically. Quaternized PEI-zirconia was able to separate oligonucleotides and oligodeoxynucleotides differing in length by a single nucleotide unit It could also separate RNAs of the same length but differing by only one deoxynucleotide. In contrast the silica-based phase was unstable at elevated temperatures (75 °C), and all retention toward anions was lost quite rapidly.