23.2 What is Thin Layer Chromatography?
Description
This article is from the Chemistry FAQ, by Bruce Hamilton B.Hamilton@irl.cri.nz with numerous contributions by others.
23.2 What is Thin Layer Chromatography?
Thin layer chromatography involves the use of a particulate sorbant on an
inert sheet of glass, plastic, or metal. The solvent is allowed to travel
up the plate with the sample spotted on the sorbant just above the solvent.
Depending on the sorbant, the separation can be either partition or
adsorption chromatography ( cellulose, silica gel and alumina are commonly
used ). The technique came to prominence during the late 1930s, however it
did not become popular until Merck and Desaga developed commercial plates
that provided reproducible separations. The major advantage of TLC is the
disposable nature of the plates. Samples do not have to undergo the
extensive clean-up steps required for HPLC. The other major advantage is the
ability to detect a wide range of compounds cheaply, using very reactive
reagents ( iodine vapours, sulfuric acid ) or indicators. Non-destructive
detection ( fluorescent indicators in the plates, examination under a UV
lamp ) also means that purified samples can be scraped off the plate and
be analysed by other techniques. There are special plates for such
preparative separations, and there are also high-performance plates that can
approach HPLC resolution. The technique is described in detail in Stahl [2]
and Kirchner [3].
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