Chromatography

Chromatography is a technique for the purification and separation of molecules in the laboratory.

Examples of common chromatography methods include: ion exchange chromatography, size exclusion chromatography, affinity binding chromatography and hydrophobic interaction chromatography.

Ion exchange chromatography separates molecules according to their overall charge. Positively charged molecules stick to the column whereas negatively charged molecules are eluted first with the buffer. Salt can be added to the column to elute the positively charged molecules afterwards. This process as a whole is called eluting.

Affinity chromatography takes advantage of the high affinity of many proteins for specific chemical groups. Affinity chromatography is more powerful than ion exchange chromatography by means of purifying proteins. Adding free binding partner elutes the protein^[1].

Types of chromatography include: two-dimensional chromatography, thin layer chromatography (TLC) and paper chromatography.

Without chromatography, and the work of Banting, Best and a biochemist called Collip (who perfected the purification), we would have no treatment for type I diabetes, that is, insulin would not have been discovered. Without chromatography we wouldn’t be able to sequence DNA, perform PCR, and many drugs and biological mechanisms would not have been discovered.