ABSTRACT
References..............................................................................................................174
Preparative thin-layer chromatography (TLC) is an offline technique because sample application, chromatographic development, and plate assessment are carried out stepwise using various devices. But, in any case, the detection is done by the use of light. The plate is illuminated by incoming light (incident light) and evaluated by the detection of the reflected light. The most convenient way to detect separated
compounds on the plate is visual examination. Unfortunately, this works only in the spectral range from 400 to 800 nm. In situ densitometry offers a way of measuring the optical density of the separated spots directly on the plate in the spectral range from 200 to 1100 nm [1-3]. Therefore, a scanner is recommended.
