Researchers in the field of chromatography have required ever more sophisticated and selective methods for removing aggregates from the monomer. Due to higher upstream titers, aggregate levels are often high, presenting challenges with regard to purity and clinical safety. One approach to solving such problems is to use new chromatography media that are optimized for higher capacity, better resolution, and greater selectivity, improving overall purification results during capture and polishing steps (He et al. 2010). An improved cation exchanger with open pore structure, fast mass transfer, and high polymer strength has been developed by Bio-Rad Laboratories for superior resolution of aggregates from monomer.