A good separation of the components of a BD–oil mixture
(0.2–4L samples without dilution) was achieved when using 10%
ethyl-acetate in hexane and silica-based TLC-plates 20cm×20cm
(see Section 2.2.5). It is recommended to use the plates on a plastic
support instead of aluminum because this facilitates the second
development in water. As an additional advantage one can mention
partial transparency of a plastic plate, where the dark spots of
separated compounds can be seen even without staining if holding
the plate against the light. The second development in water
(or slow tilting of the plate into a water bath for 2–4 min) displaces
the remaining organic solvents from the gel and prevents
development of a heavy irregular background under the following
staining (see Section 2). Finally, the stained plate should be washed
with water to remove the excessive permanganate. An example of
separation and staining is shown for a five-component mixture in