Scale of synthesis	0.02 µmol	0.05 µmol	0.20 µmol	1.0 µmol	15 µmol
Length restriction	N/A	10-55	10-55	10-55	10-55
Minimum yield 20 nucleotides	N/A	3 OD	6 OD	15 OD

 

Reverse-phase HPLC operates on the same principle as the RPC. The basis of the separation is the difference in hydrophobicity between full-length product (which contains a 5'-DMT) and truncated sequences (without DMT groups). The hydrophobic DMT group is removed after the purification.The capacity and resolving properties of HPLC columns are more powerful than obtained by RPC. The typical yield is a product of 90-97% purity. As with RPC, RP-HPLC is usually not recommended for purifying oligos longer than 55 bases. This is due to the risk of secondary DNA structures disturbing the purification process. See Fig. 3.

 

Fig. 3 Crude oligo in purification process. The large peak is collected. This peak contains only full-length product. The residual, containing truncated failure sequences, is wasted.