This fast, simple LC-MS/MS workflow for the direct analysis of polar pesticides in spinach provides good retention and peak shape over hundreds of matrix injections.
Protein Therapeutics: Antibody Characterization with ECD
June 10th 2024Labile post-translational modifications are better preserved using ECD than conventional MS fragmentation techniques such as collision-induced dissociation (CID). Common modifications, such as glycosylation and phosphorylation, can impact the safety, efficacy, and binding activity of monoclonal antibodies but are challenging to identify. Stephen Sciuto from Agilent Technologies and colleagues analyzed tryptic digests of NIST mAb and Infliximab using an 6545XT Q-TOF mass spectrometer in ExD or CID mode. ECD provided higher sequence coverage than CID, reaching 100% for glycosylated peptides in Infliximab. The ability to pinpoint glycosylation sites using fragment ions demonstrates the power of ECD for characterizing glycopeptides.
Monoclonal Antibodies: Faster Analysis with Microdroplets
June 10th 2024The first reported combination of microdroplet reactions with ECD fragmentation offers a quicker way to analyze monoclonal antibodies for disease treatments. Thomas Walker from Agilent Technologies and co-workers demonstrate the use of an Agilent Jet Stream electrospray ionization source to facilitate in-spray chemical reduction and protease digestion of monoclonal antibodies. Downstream fragmentation of the microdroplet reaction products with ECD provided rapid characterization of intact antibodies in minutes. Efficient ECD fragmentation yielded rich sequence information including evidence of disulfide bond connectivity and confirmation of key sequences called complementary determining regions. These results highlight this method’s potential for fast and cost-effective antibody characterization with minimal sample preparation.