Thin Layer Chromatography - Measurement Methods 2


This procedure is depicted in the lower chromatogram in figure 24. Sliced area integration is a procedure that attempts to maintain the accuracy of area integration and, at the same time, utilize some of the advantages of peak height measurement. It is clear that slice integration can reduce some of the errors caused by peak overlap. This procedure, however, requires very careful selection of the limits used in the computer integration protocol, but, nevertheless, if carefully carried out can be a useful compromise between peak height and peak area measurements when using scanned data from a TLC plate.


Figure 24. Different Forms of Peak Integration


There are a many published applications described in the literature employing TLC for quantitative analysis, many of which, although applied to different materials are, from the point of view of the technique, very similar in nature. The following examples are taken from reports mostly published either in the Analyst, Analytical Chemistry or the Journal of Planar Chromatography and these journals, together with the Journal of Liquid Chromatography are recommended as reliable sources of application information for those starting to use TLC for quantitative assays. The versatility of the technique is demonsrtrated by the widely different application areas from which the examples are taken.