What are the various purification options?
Top Following synthesis of the oligonucleotide, the resulting product contains full-length oligos, failed sequences, and reaction salts. The purification procedures therefore aim to remove these failed sequences and/or the reaction salts. It should be noted, unfortunately, that a consequence of purification is the concomitant loss of full-length products. Desalting-Desalted – Oligos are purified by either gel filtration or EtOH precipitation. Theses methods remove the reaction salts but not the failed sequences. Reverse phase cartridge purification (RP) – Oligos purified using RP have been synthesized such that the last trityl protecting group is still attached. Failed sequences do not receive a 5 trityl group. Thus, oligos that possess a 5 trityl group bind the column and the failed sequences flow through the cartridge. RP pure oligos have most of the failed sequences removed and are approximately 90 to 95% pure. Reverse Phase HPLC – This method also uses the 5 trityl protecting group
