Native IEX-MS analysis of monoclonal antibodies using YMC Accura BioPro IEX SF columns

Direct coupling of ion exchange chromatography (IEX) to mass spectrometry (MS) is a game-changer for simplifying workflows and minimising artefacts caused by lengthy isolation steps. While volatile buffers and salts make coupling possible, the high salt concentrations typically used in IEX pose a challenge for MS compatibility. To overcome this, nano-electrospray ionisation (nanoESI) sources, which tolerate high salt concentrations, can be combined with systematic setups like flow splitters (reducing flow to sub-μL/min). However, even greater performance gains can be achieved using IEX columns with smaller inner diameters (ID) and bioinert coated hardware. This setup yields sharper peaks, higher resolution, and optimal recovery—even from the first injection.