What principle does chromatography rely on?

Chromatography relies on the principle of different rates of movement through a medium. This technique is used to separate mixtures into their individual components based on how various substances interact with a stationary phase and a mobile phase.

In chromatography, the sample mixture is placed on a stationary medium, which could be a solid or a liquid. As the mobile phase (a solvent or gas) moves through or along this medium, different components of the mixture will travel at different speeds depending on their unique chemical properties, such as their polarity, size, and affinity for the stationary phase.

This differential movement allows for the separation of substances. For example, in paper chromatography, the solvent carries the substances up the paper where they spread out; some will travel further than others based on their solubility and interaction with the paper, thus resulting in a separation of the components. Therefore, the correct understanding of chromatography hinges on how substances behave differently when subjected to the same conditions within the chosen medium.