what is the physical principle used in chromatography?

Question

what is the physical principle used in chromatography?

Answer 1

The principal is called partition, which is a kind of equilibrium. only a certain fraction of a substance is in the moving phase, while the rest is absorbed on the support. The Rf value, which is the rate at which the substance moves as a fraction of the rate of movement of the moving phase, is simply equal to the fraction of substance molecules that are not stuck on the support.

The moving phase is sometimes a gas and sometimes a liquid.. Different substances stick more or less firmly to the support. For liquid chromatography, you also need to consider how strongly substances interact with the liquid.

The repeated equilibria set up means that chromatography acts rather like a very large number of fractional distillations, or fractional crystallisations.