ABSTRACT
The drawbacks to using reversed-phase chromatography are that the trityl-OH protecting group on the 5' end is very hydrophobic and requires removal of the group after chromatography, it is time-consuming, and acetic acid may cause depurination and undesired chain cleavage at depurination sites. Reversed-phase purification with trityl-off is straightforward. However, the hydrophobicity of the main oligonucleotide and the shorter chains are not significantly different, making the separation quite poor. PAGE provides the best oligonucleotide separation, but it is very labor intensive, time-consuming, and difficult to scale up and the yield is often low.
