Antibody-purity analysis is critical to successful development of monoclonal antibody (MAb) biopharmaceuticals. Their manufacture involves processes of protein purification, formulation, and stability evaluation. All those processes need highly accurate and reproducible analytical results to support decisions made by product developers and manufacturers. A common technology for antibody-purity analysis is sodium-dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). In this technique, a polypeptide chain binds SDS proportionally to its relative molecular mass. The detergent nature of SDS denatures proteins by disrupting their noncovalent…