Microchip electrophoresis separation coupled to mass spectrometry (MCE-MS) for the rapid monitoring of multiple quality attributes of monoclonal antibodies

Therapeutic monoclonal antibodies (mAbs) are highly heterogeneous as a result of posttranslational modifications (PTMs) during bioprocessing and storage. The modifications that impact mAb product quality are regarded as critical quality attributes and require monitoring. The conventional LC-mass spectrometer (MS) method used for product quality monitoring may require protein A purification prior to analysis. In this paper, we present a high-throughput microchip electrophoresis (<4 min) in-line with MS (MCE-MS) that enables baseline separation and characterization of Fc, Fd', and light chain (LC) domains of IdeS-treated mAb sample directly from bioreactor. The NISTmAb was used to optimize the MCE separation and to assess its capability of multiple attribute monitoring. The MCE-MS can uniquely separate and characterize deamidated species at domain level compared to LC-MS method. Two case studies were followed to demonstrate the method capability of monitoring product quality of mAb samples from stability studies or directly from bioreactors.