Such sanitization issues occurred mainly in the polyether class, in which all precursors, except polyacetal, are cyclic structures. As shown in 5b, over 90% of the structures were incorrectly assigned due to issues associated with the ring-opening process. In case of the poly(hexamethylene oxide) polymer, see Fig. ), the sanitization process did not produce a SMILES structure for visual evaluation. We have observed improper SMILES sequences in 2 cases and improper ring-opening process in 8 cases. In the case of poly(propylene glycol), the sanitization step has generated a proper SMILES structure; however, the ring-opening process was performed in a manner that has led to an incorrect assignment of the tail position.