In chromatography, what is the stationary phase?

In chromatography, the stationary phase refers to the phase that remains fixed while the mobile phase moves through it. This phase is typically composed of a solid or a liquid supported on a solid surface. As the mobile phase passes through the stationary phase, components of the mixture being separated interact differently with the stationary phase, leading to separation based on differences in properties such as polarity, size, or affinity. The stationary phase plays a crucial role in achieving the desired separation in chromatographic processes.