Immunoaffinity chromatography (IAC) has long been regarded as a highly specific method for the purification of biological agents. In this technique, a chromatographic column is used that contains antibodies or antibody-related reagents as the stationary phase. The high selectivity of antibodies in their interactions with other molecules, and the ability to produce antibodies against a wide range of solutes, has made IAC popular as a tool for the purification of biomolecules like hormones, peptides, enzymes, recombinant proteins, receptors, viruses, and subcellular components (1–8). In recent years, the high selectivity of IAC has also made it appealing as a means for developing a variety of specific analytical methods (3,9,10). An important item to consider in the development of any IAC method is the technique used for coupling the antibodies to the chromatographic support material. One common approach