Column chromatography is frequently used by organic chemists to purify liquids (and solids) . An impure sample is located onto column of adsorbent , such as silica gel or alumina. An organic solvent or a mixture of solvents ( the eluent ) flows down through the column.

Separation of mixtures into their components and purification of compounds can be achieved through the process of chromatography. Chromatography is a technique that is based on the differential adsorption of components of a mixture onto an adsorbent material.

Here is a detailed explanation of the process of chromatography:

1. Principle of chromatography:
- Chromatography is based on the principle that different components of a mixture have different affinities for the adsorbent material.
- The adsorbent material can be a solid (such as silica gel or alumina) or a liquid (such as a liquid solvent).
- The mixture to be separated is called the sample and is applied to the adsorbent material.

2. Stationary phase and mobile phase:
- Chromatography involves two phases: the stationary phase and the mobile phase.
- The stationary phase is the adsorbent material, which remains fixed in place.
- The mobile phase is a liquid or gas that is allowed to flow over the stationary phase, carrying the sample with it.

3. Adsorption and desorption:
- When the sample is applied to the stationary phase, the different components of the sample adsorb onto the adsorbent material to different extents.
- The components that have a higher affinity for the adsorbent material will adsorb more strongly and move more slowly through the stationary phase.
- The components that have a lower affinity for the adsorbent material will adsorb less strongly and move more quickly through the stationary phase.

4. Separation and elution:
- As the mobile phase flows over the stationary phase, the components of the sample are carried along with it.
- The components that have adsorbed more strongly will be eluted later and will appear as separate bands or spots on the adsorbent material.
- The components that have adsorbed less strongly will be eluted earlier and will appear as separate bands or spots further up the adsorbent material.

5. Detection and analysis:
- Once the components have been separated, they can be detected and analyzed.
- This can be done using various techniques, such as UV-visible spectroscopy, mass spectrometry, or flame ionization detection.

In summary, chromatography is a process that utilizes the differential adsorption of components of a mixture onto an adsorbent material to separate and purify compounds. It is a versatile technique that is widely used in various fields, including analytical chemistry, biochemistry, and pharmaceutical research.