A growing number of separations’ scientists and process developers are looking beyond protein A sorbents for capture and initial purification of monoclonal antibodies. A variety of strategic and operational goals have prompted examination of alternative immunoglobulin-selective sorbents. Most broadly, many workers wish to eliminate design considerations associated with leached protein A. Also cited is a preference for sorbents that can withstand stringent cleanup using 1 M sodium hydroxide. In some applications, it is desirable to avoid the low-pH elution conditions typically employed with protein A sorbents — conditions that can foster aggregate formation. In still other cases, the target antibody may bind poorly to protein A. Finally, there may be interest in evaluation of immunoglobulin-selective sorbents less costly than protein A sorbents…