Chromotography

• Chromotography refers to a variety of techniques used to purify biological molecules, such as proteins and nucleic acids.
• A substance to be purified is suspended in a liquid medium (mobile phase), and is passed on to a column of matrix, such as beads (immobile phase). The substance to be purified interacts with the matrix and the interaction is used as a basis of separation.
• In an ion exchange chromatography, the ionic charge of the substance is used as a basis of separation.
• In Gel filtration chromatography makes use of the size of the molecule as the basis for purification.
• In affinity chromatography, it uses special and specific interactions between two molecules as the basis of purification. Examples are, antibody with antigen, enzyme with substrate or receptors with ligands.
• The high-performance liquid chromotography or HPLC is a high-resolution type of chromotography that uses high pressure to drive the mobile phase into the tightly packed matrix. Substances separated by these processes are high purity.