Densitometric Evaluation

In the 1960s planar chromatograms were evaluated quantitatively with the help of electrophoresis photometers, some of which had to be modified. The major disadvantage of these instruments was the fact that they used visible light and therefore only coloured substances could be measured. This required some sort of visualization technique to be used.

The first densitometers specifically designed for TLC were those by Zeiss (1965), Shoeffel (1967), CAMAG (1978) and Shimadzu (1979). These devices were fitted with a monochromator, utilized ultraviolet light and measured in the reflection mode, which has advantages over the transmission mode.

In 1976 the first experimental set-up for evaluation of planar chromatograms by video technology was described by Devenyi. In the following years instruments originally designed for the evaluation of elec-trophoresis gels were adapted for use in TLC. TLC-specific video systems have been available since 1988 (Uniscan, Analtech).

Modern scanning densitometers as well as state-of-the-art video densitometry are discussed in the section on Thin-layer (planar) chromatography - instrumentation.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

Get My Free Ebook

Post a comment