Thin-layer chromatography is (TLC) is an adsorption chromatography technique used to separate non-volatile mixtures. Thin-layer chromatography is performed on a sheet of glass, plastic, or aluminium foil, which is coated with a thin layer of adsorbent material, usually silica gel, aluminium oxide(alumina) or cellulose. This layer of adsorbent is known as the stationary phase.