What is chromatography and what are the types of chromatography?

Chromatography is a separation technique used to isolate the individual components in a mixture, in which a mobile phase carries the mixture travelling through a stationary phase at different speeds. The differential partitioning between the mobile and stationary phases, which is referred to as a compound’s partition coefficient, results in differential retention on the stationary phase, causing them to separate.

Chromatography is categories as column chromatography and planar chromatography based on their different bed shape.

Column chromatography, with its stationary bed contained in a tube, can be further divided into gas chromatography and liquid chromatography based on the physical state of mobile phase. Liquid chromatography is now being widely used in biochemistry, pharmaceuticals and food analysis as a standard separation and purification method.

Planar chromatography, on the other hand, presents its stationary phase on a plane, such as a paper (paper chromatography) or a glass plate (thin-layer chromatography). It is usually cheaper, less sophisticated, and easier to manipulate than the column chromatography, which is constantly used in labs for fast screening of a series of compounds.