Manufacturers strive toward cost-effective purification of target molecules and a high level of confidence that their biologics are safe and not compromised by the presence of endogenous retrovirus-like particles or adventitious viruses (1). Reliable reduction of viral particles throughout downstream purification processes must be ensured through different techniques such as chemical treatment, filtration, and chromatography. Common monoclonal antibody (MAb) purification schemes use both cation- and anion-exchange chromatography steps (CEX, AEX). Although CEX (to remove product- and process-related impurities) is not…