Highlights

•  During the product development of monoclonal antibodies in biopharmaceutical industry it is important to monitor the effect of process changes on antibody protein structure.

• Some modifications such as oxidation of methionine, isomerization of aspartate and asparagine-linked glycosylation in complimentary determined region (CDR) and fc region, are considered as the critical quality attributes (CQA).

• Therefore, a good LC-MS peptide mapping method is required not only to confirm the desired protein structure but also to semi-quantitate these modifications by comparing with a reference product lot.

• The results in the current study clearly demonstrated that the 0.5-hour PCT assisted tryptic digestion significantly minimized modification artifacts and reduced chromatographic interference.

• Meanwhile the 0.5-hour PCT approach was successfully applied to deglycosylation, showing completely removal of the N-glycans from the Asn₃₀₁ in the heavy chains of monoclonal antibody with no impact on the tryptic digest. 

• This efficient sample preparation can be applied to both peptide mapping and de-glycosylated peptide mapping for monoclonal antibodies.