Affinity Chromatography (AFC) is based on the specific adsorption of a molecule to a ligand of macromolecule.
Almost all biological molecules can be purified on the basis of specific interaction between their chemical or biological structure and a suitable affinity ligand.
Typical molecular pair are antigens, antibodies, enzymes and sugars with lectins.
AFC media have ligands that are bonded via a spacer arm to the packing material. A specific biological molecule is then reversibly adsorbed to the ligand and is eluted either by competitive displacement or by a change in the conformation of the molecule through a change in pH or ionic strength.
Because of the intrinsic high selectivity of AFC, it is suitable for specific separation problems and provides high purification yields. The advantage of AFC is the simplicity of the elution with a single-step gradient.