The separation chamber contains four main components; aholding unit, a hydraulic unit, a tray-like layer cassette, and anattached drain valve [34,37,39]. The thin-layer plate is placedin the cassette and then inserted into the separation chamber,which automatically seals the layer by the pressurized plasticsheet. Different cassettes facilitate the use of 20 cm-long platesof different widths for linear development (effective plate lengthbetween the inlet and outlet troughs is 18.3 cm), bi-directional lin-ear development (mobile phase is applied at the center and flowssimultaneously in both directions toward opposite edges of thelayer; two-dimensional development (sequential development ofthe layer in orthogonal directions with drying of the layer between