Thin-layer chromatography (TLC) plate, showing separated components (colours). TLC is a chromatography technique used to separate non-volatile mixtures. It is performed on a sheet of glass, plastic, or aluminium foil coated in a thin layer of adsorbent material (the stationary phase). The sample is applied to the plate and a solvent (the mobile phase) is drawn up the plate via capillary action. Different components move up the plate at different rates, causing them to separate, as shown here.