Use of diluted anion-exchange and hydrophobic properties in separating synthetic single-stranded oligodeoxyribonucleotides on mixed-ligand stationary phases

Summary

Mixed-ligand or “mixed-interaction” stationary phases are composed of bonded silanes possessing both ionic and hydrophobic character. The complex retention properties exhibited by these phases have been particularly useful in separating large biomolecules, such as synthetic single-stranded oligodeoxyribonucleotides. By isolating the individual properties of separate ligands present in mixed-ligand stationary phases a better understanding of the heterogeneous surface was sought. Specifically a dilute anion-exchange mixed-ligand phase of 5% surface coverage showed dramatically different selectivity for oligomers compared to hydrophobic stationary phases. Of particular interest was the increased selectivity observed in separating oligonucleotides differing on the 3′ end over conventional reversed-phases supports.