Affinity chromatography is a separation technique based on the use of specific and selective immobilized ligands able to associate reversibly to a desired biomolecule. Samples are passed through affinity columns that are equilibrated with a buffer favouring interaction between the immobilized ligand and the target biomolecule. Unrelated contaminants will be eluted in the column void volume and a suitable buffer change will lead to elution of the adsorbed biomolecule.