Figure 4.
(a) Mass spectrum of impurity identified at m/z 1843 and (b) modeled data for (n−1) short-mer phosphorothioate oligonucleotide with chemical composition of C226H226N68O127P22S22. This chemical composition is consistent with the (n−1) short-mer sequence 5′-CG TCG TTT TGT CGT TTT GTC GTT-3′.