Why don't you offer additional purification for your ddRNAi oligos?
ddRNAi oligos are long perfect hairpins. Purification is nearly impossible. In fact, purification can enrich for bad oligos which are missing a base, form an imperfect hairpin, and denature easier. We use a high fidelity synthesis platform for the production of these oligos and that cuts down on the need for purification by decreasing the amount of truncated product.