An Introduction to Chromatography

 CHROMATOGRAPHY

• Chromatography is a physico – chemical method used for the separation and identification of compounds in a mixture using stationary phase (filter paper, silica gel or alumina) and mobile phase (gas or solvents).
• The word chromatography was obtained from the Greek word which means “Colour writing” (Chroma – colour; Graphin – writing).
• The word chromatography was first introduced by Mikhail Tsweet in 1906. He used to separate the pigments from plants.
• Chromatography is having wide number of applications in both physical and biological sciences.

Stationary Phase

• The stationary phase is one of the two phases forming a chromatographic system.
• It may be a solid, a gel or a liquid. If a liquid, it may be distributed on a solid.
• This solid may or may not contribute to the separation process. The liquid may also be chemically bonded to the solid.

Mobile Phase

• A fluid which percolates through or along the stationary bed, in a definite direction.
• It may be a liquid (Liquid Chromatography) or a gas (Gas Chromatography) or a supercritical fluid (Supercritical-Fluid Chromatography).
• In Gas chromatography the expression Carrier Gas may be used for the mobile phase.
• In elution chromatography the expression Eluent is also used for the mobile phase.

Chromatogram

• A graphical or other presentation of detector response, concentration of analyte in the effluent or other quantity used as a measure of effluent concentration versus effluent volume or time. In planar chromatography "chromatogram" may refer to the paper or layer with the separated zones.