Scale of synthesis	0.02 µmol	0.05µmol	0.20 µmol	1.0 µmol	15 µmol
Length restriction	5-35	5-45	5-45	5-45	5-45
Minimum yield 20 nucleotides	2 OD	4 OD	10 OD	60 OD

 

Separation on a reverse-phase cartridge (RPC) offers the next level of purity (typically 80-90%). The level of purity for RPC is almost equivalent to that provided by HPLC and the recovery is often higher. 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. Cartridge purification is not recommended for oligos > 45 bases. For most high-resolution applications, cartridge purification will provide the necessary purity level. See fig.2.

 

Fig. 2 RP-HPLC chromatogram of a M13Rev primer previously purified by RP-Cartridge.   Notice that the failure products normally seen at 3 and 5 minutes are almost completely eliminated.