Size-exclusion chromatography-mass spectrometry with m-nitrobenzyl alcohol as post-column additive for direct characterization of size variants of monoclonal antibodies.

Size-exclusion chromatography (SEC) is commonly used to monitor low molecular weight fragments and aggregates present in recombinant monoclonal antibody (mAb) biopharmaceuticals. It has been previously demonstrated that SEC could be coupled with mass spectrometry (MS) to directly measure the molecular weights of these protein species to aid in their identification. However, the use of certain mobile phase modifiers led to compromised sensitivity in MS detection.