Thin Layer Chromatography - Chromatography Apparatus
Thin layer chromatography was invented as an uncomplicated form of chromatography that would be reasonably affective for separating relatively simple mixtures, would give approximate quantitative results and would be easy and inexpensive to use. As a consequence, the technique (as it was originally envisaged) requires low-priced apparatus, is inexpensive to operate and achieves the purpose its originators intended.
Unfortunately, attempts have been made to obtain results from TLC similar to those obtainable from LC that has resulted in the cost of the apparatus being increased greatly with very limited improvement in results. TLC is best used as the simple, rapid semi quantitative separation technique it was devised to be and if greater resolution and improved accuracy is required then the technique of LC should be used.
Thin Layer Chromatography Chambers
In practice, the sample is spotted on the edge of the TLC plate which is then dipped into a solvent that migrates along the plate surface by tension forces, developing the separation in the process. It is important to prevent the solvent evaporating from the plate surface during development, as this would change the composition of the developing solvent. If the solvents were volatile and the evaporation rate was sufficiently high, the migration rate would be modified and anticipated separation not achieved. A diagram of two simple thin layer chromatography development chambers is shown in figure 3.