Chromatography,a greek word which means color writing [chrom:color graphy:writing] is collective term for set of laboratory techniques used for separation of mixtures. This process use to separate molecules based on physical properties of molecules such as

1. Mass
2. Charge
3. Hydrophobic interactions
4. Affinity for ligands or substrates

The basic idea here is that different components of a mixture interact differently with a common medium (it can be a solid substrate or a liquid medium). The differences in the interactions between the mixture and the medium are utilized to separate the components from the mixture. By allowing a mixture to run through a column, which is packed with a suitable medium, the components can be separated out. Among all the chromatographic techniques column chromatography is widely used owing to its low cost and disposability of the stationary phase.

Definition's of some general terms used in these techniques:

1. Elute: is the mobile phase leaving the column
2. Analyate: is the substance to be separated during chromatography
3. Mobile phase: This consists of solvent and sample which needs to be separated,this phase moves along the column in a definite direction.Mobile phase may be liquid,gas or fluid
4. Stationary phase: Phase which remains stationary called stationary phase,generally packing material used to fill the column acts as stationary phase.

This experiment demonstrates how inter-atomic interactions are used to purify mixtures. A simplified version of the column chromatography is used here to provide the atomistic details of purification of a binary mixture (a mixture consisting of two types of atoms).