IMAGE. Commercial TLC plate after development in normal
lighting.
IMAGE. Same TLC plate held under a UV lamp -- Note the
appearance of additional spots.
If the spots can be seen, outline them with a pencil.
If no spots are obvious, the most common visualization technique is to hold the plate under a UV lamp (CAUTION: Do not look directly into the lamp.).
Many organic compounds can be seen using this technique. Commercially made plates often contain a substance which aids in the visualization of
compounds. In these plates, the silica gel is coated with a compound that
will fluoresce under an ultraviolet lamp. The spots from a sample will show
up as dark regions on commercial plates because they are covering the
fluorescent material.
