Protein A affinity chromatography is a well-established technology that is used extensively for large-scale purification of monoclonal antibodies (MAbs). With this mode of chromatography, very high product purity can be achieved in a single, relatively simple unit operation. A solution containing the target protein of interest is applied to a liquid-chromatography column at near-neutral pH, and one or more wash steps follow to lower product- and process-related impurities (1). Product is eluted through application of a low-pH buffer. Finally, the…