Preparation and chromatographic behavior of a bifunctional continuous rod for weak cation exchange and immobilized metal affinity chromatography

A procedure for the preparation of a bifunctional continuous rod for weak i on exchange chromatography (WCX) and immobilized metal affinity chromatogra phy (IMAC) is presented. Without chelated metal, from the retention behavio r of proteins, the rod, which carries iminoacetic acid and iminodiacetic ac id (IDA) groups was found to be a relatively strong cation exchanger and ex hibits an excellent separation of proteins at the flow rates of both 1.0 mL /min and 8.0 mL/min, respectively. When Cu(II), Zn(II), or Ni(II) was chela ted, the rod displayed the property of IMAC and the selectivity for protein separation to be different from that obtained from the naked rod. The effe cts of pH and temperature on protein retention were investigated on both th e naked and metal chelated rods. An abnormal increase in retention times of proteins was found under the condition of very high pH and very low pH on the metal chelated rods.