Separation of nucleotide oligomers by unitary anion-exchange

This paper is the first report on the retention behavior of synthetic oligonucleotides and nucleotide oligomers on a continuous-bed-matrix, strong-anion-exchange column. The separation mechanism is predominantly an anion-exchange process, but hydrophobic interaction plays a role as well. The separation is based on the chain length of the oligonucleotide. Both the addition of organic mobile phase modifiers and changes in column temperature affect the retention of oligomers significantly. A volatile buffer system (e.g., triethylamine acetate) could be employed to purify oligonucleotides, and no desalting procedure would be required after the column separation step. The recoveries from the separation are 70% or higher. The maximum loading capacity of an analytical column (35 × 7-mm i.d.) was found to be more than 366 μg.