The principle of chromatography is based on the fact that different substances in a mixture move at different rates when carried by a mobile phase over a stationary phase. This difference in movement allows the substances to be separated and identified.
Simple Explanation:
- A mixture contains different substances.
- The mixture is placed on a stationary phase (like paper, silica gel, or a column).
- A mobile phase (liquid or gas) moves through the stationary phase.
- Each substance interacts differently with the stationary phase and the mobile phase:
- Some stick strongly to the stationary phase → move slowly.
- Some stick weakly → move faster with the mobile phase.
- This difference in speed causes the separation of components in the mixture.
Key Idea:
- Separation happens because substances have different affinities (attraction) for the stationary and mobile phases.
- Substances that are more soluble in the mobile phase move faster.
- Substances that are more attracted to the stationary phase move slower.
In Short:
Chromatography works on the principle that different substances move differently through a stationary phase when carried by a mobile phase, allowing them to be separated and analyzed.