Human IgG is an important plasma protein produced worldwide on a large scale. Affinity chromatographic processes are not commercially used for the production of IgG since the ligands tried so far hinder their application to pharmaceutical products. Immobilized ion affinity chromatography (IMAC) has the potential to circumvent these problems. The adsorption of human IgG onto IDA-Sepharose immobilized Cu2+, Ni2+, Zn2+, and Co2+ with MOPS, phosphate, MMA, and Tris-HCI adsorption buffering systems is reported. Adsorption of high purity IgG was high for all metals irrespective of the buffer system used. Elution of IgG was similar for all buffer systems except for the case of pH elution when copper was the ligand. Isoeletrocfocusing showed the presence of molecules of low pI in the flowthrough of the chromatographic runs with Ni2+-phosphate-acetate, Ni2+-MOPS-imidazole and Zn2+-MOPS-imidazole systems. Chromatography runs with human plasma indicated the potential of this technique for IgG purification. (C) 2002 Elsevier Science Ltd. All rights reserved.