What is elution in column chromatography?

In column chromatography, elution is the process by which components of a mixture are transported through the stationary phase by a continuously flowing mobile phase.12

As the mobile phase moves through the column, the mixture's components are partitioned between the stationary and mobile phases based on their relative affinities for each. Components with a stronger attraction to the stationary phase migrate more slowly, while those with a weaker attraction are flushed out more rapidly.23

The term "elute" refers to the migration of a solute through and out of the column. The emerging mobile-phase stream containing these separated components is known as the eluate. The time required for a specific solute to migrate from the point of injection to the column outlet is called its retention time. In practice, a detector often monitors the eluate as it exits, recording the concentration of solutes over time to produce a chromatogram.1