migration

The term "migration" in chemistry refers to the movement of charged particles, such as ions, within a substance. This movement is often driven by an electric field, a process known as electromigration.

In the context of chromatography, migration describes how different components of a mixture separate. This separation occurs because each component moves at a different rate, influenced by its affinity for a moving fluid (mobile phase) and a stationary phase. Solutes that are more attracted to the mobile phase travel faster, while those attracted to the stationary phase are retained longer. This differential migration allows for the separation and analysis of complex mixtures.12

Cell membranes also exhibit selective permeability, controlling the movement of substances into and out of the cell. While small, lipid-soluble molecules can pass through easily, charged ions and larger molecules require specific transport systems facilitated by membrane proteins.3