Middle-Up Characterization of the Monoclonal Antibody Infliximab by Capillary Zone Electrophoresis–Mass Spectrometry
CZE–ESI‑TOF‑MS for the characterization of the mAb infliximab and its variants is presented. Infliximab was analyzed using a middle-up approach involving either reduction or digestion with the enzyme IdeS. A multilayer capillary coating of PB-DS‑PB in combination with a background electrolyte of 40% acetic acid provided efficient separation of the obtained antibody fragments, that is, LC and HC, as well as F(ab’)2 and Fc/2 parts. C-terminal lysine variants were also resolved. Recorded mass spectra of HC and Fc/2 fragments permitted assignment of 13 glycoforms and provided a quantitative profile, with G0F the most abundant glycoform (~50%). CZE–ESI-TOF-MS represents an efficient means for the straightforward analysis of a monoclonal antibody and its proteoforms.