IgG Assay by Affinity Chromatography
Selective separation of a target biomolecule from a highly complex biological matrix is based on the use of an affinity ligand that has been immobilized on a stationary phase packed in a short column. The ligand can be specific so that the antibody binds to only one epitope, or a group type ligand such as nucleotide analogues or Protein A or Protein G that will capture a group of selected compounds. Thus affinity ligands may be selected to serve a specific  purpose, such as when immobilized antibody is used for antigen purification, or conversely when immobilized antigen is used for antibody purification.