Advancement in liquid adsorption chromatography:

Advancement in liquid adsorption chromatography was reported in the form of affinity chromatography. Within this the column material, a gel such as material, is attached along with a biospecific material through a spacer arm. This biospecific material is known as a ligand. The ligand selectively picks up a biological molecule from the mixture to form a complex. A desired biological molecule could be eluted through modest changes such as pH or ionic strength in the eluant.

An important branch of liquid chromatography is ion exchange chromatography. This includes exchange of ions, cations or anions, among an insoluble matrix and the solution which comes in contact with it. The insoluble material which carries exchangeable cations and anions is known as ion exchange. Those carrying exchangeable cations are known as cation exchangers and those with exchangeable anions are known as anion exchangers. Those are amphoteric exchangers that are capable of both cation and anion exchange. Ion exchange, along with a extremely few exceptions, is a reversible process. In contrast to adsorption, ion exchange is a stoichiometric process. Every ion removed from the solution is replaced by an equivalent amount of another ionic species of the similar sign. Ion exchangers are organic and inorganic, natural and synthetic. Most of the ion exchangers in daily use are organic resins.