chromatography

Chromatography
Chromatography is an analytical technique commonly used for separating a mixture of chemical substances into its individual components, so that the individual components can be thoroughly analyzed.
Chromatography techniques:
There are different techniques in chromatography. But common technical requirements to all the types include
1. Stationary phase: The stationary phase is one which stays motionless and allows sample to move over it. This phase used can be solid or liquid. If it is a solid stationary phase, it should have particles of uniform size and shape. More over their shape should be preferably spherical. If a liquid is used as the stationary phase, the liquid is spread as an uniform layer on the solid background. The chromatography columns are house the stationary phases in all the types of chromatography except in paper and thin layer chromatography as they do not have a column.
2. The mobile phase: This is the chromatography part that helps the sample to move over the stationary phase. The mobile phase used is a liquid or gas and it should be free of particle matter and other impurities. Technically, the mobile phase should have opposite polarity to that of stationary phase material. I.e. if stationary phase is of polar in nature, then mobile phase has to be non-polar and vice-verse. In normal phase chromatography, the mobile phase is non-polar in nature while in reverse phase the mobile phase is polar in nature.