When using affinity chromatography for purification, we need to fully evaluate the structure and affinity site of the target product. For example, some recombinant proteins will introduce histidine tags during the carrier construction stage, and affinity packing materials containing nickel ions can be used for capture; while for recombinant proteins containing GST tags, glutathione affinity chromatography can be used. For the capture of therapeutic antibodies (monoclonal antibodies, double antibodies, and polyantibodies), it is necessary to select chromatography media based on the antibody structure. For example, for antibodies containing the complete antibody structure (including the Fc region), protein A and protein G affinity chromatography can usually be used for capture.