Rotation planar chromatography was developed largely as a preparative technique, although it can be used for analytical separations [32,33]. Rotational planar chromatography uses centrifugal forces to move the mobile phase through the layer created by spinning the plate around a central axis at 80–2000 rpm. The mobile phase is fed to a center point on the layer and samples appliedeither as spots on the periphery of a circle around the solvent entry position or injected by a valve into the mobile phase supply (single sample separation). The mobile phase velocity is a function of the rotation speed and the feed rate of the mobile phase to the layer.The ultimate velocity of the solvent front is limited by the amount of solvent that can be kept within the layer without flowing over the surface. A quartz lid slightly above the rotating layer allows the separation progress to be observed for colored and UV-absorbing compounds. A collection system fixed to the rotor allows separated fractions to be collected as they leave the layer for preparativescale applications. The more advanced instruments manufactured by Hitachi (ClC-5) and Rotachrom are no longer in production. Simpler instruments from Harris Research (Chromatron) and Analtech (Cyclograph), Fig. 9, are used predominantly in synthetic organic chemistry and natural product chemistry laboratories.