Establishing Multi-Dimensional LC-MS Systems for Versatile Workflows to Analyze Therapeutic Antibodies at Different Molecular Levels in Routine Operations

<b>Background/Objectives:</b> Multi-dimensional liquid chromatography coupled with mass spectrometry (mD-LC-MS) has emerged as a powerful technique for the in-depth characterization of biopharmaceuticals by assessing chromatographically resolved product variants in a streamlined and semi-automated manner. The study aims to demystify and enhance the accessibility to this powerful but inherently complex technique by detailing a robust and user-friendly instrument platform, allowing analysts to switch seamlessly between intact, subunit, and peptide mapping workflows. <b>Methods:</b> Starting from a commercially available Two-Dimensional Liquid Chromatography (2D-LC) system, we introduce specific hardware and software extensions leading to two versatile mD-LC-MS setups, in slightly different configurations. The technique's efficacy is demonstrated through a case study on a cation exchange chromatography method assessing the charge variants of a bispecific antibody, isolating peak(s) of interest, followed by online sample processing, including reduction and enzymatic digestion, and subsequently mass spectrometry analysis. <b>Results:</b> The accuracy and reproducibility of both mD-LC-MS setups proposed in this study were successfully tested. Despite the complex peak patterns in the first dimension, the systems were equally effective in identifying and quantifying the underlying product species. This case study highlights the routine usability of mD-LC-MS technology for the characterization of (ultra) high-performance liquid chromatography (UHPLC) of therapeutic biomolecule. <b>Conclusions:</b> The demonstrated reliability and accuracy underscore the practicality of mD-LC-MS for routine use in biopharmaceutical analysis. Our detailed description of the mD-LC-MS systems and insights simplify access to this advanced technology for a broader scientific community, regardless of expertise level, and lower the entry barrier for its use in various research and industrial settings.