Chapter 5 Planar chromatography

Abstract

Thin-layer chromatography (TLC) and paper chromatography (PC) differ from other chromatographic techniques in the planar arrangement of the stationary phase. Otherwise, practically all the chromatographic principles and, in TLC, all the types of sorbents are similar to those used in column chromatography (CC). The planar (flat-bed) arrangement has several advantages, such as simplicity, flexibility, parallel analysis of a large number of samples, two-dimensional development, and applicability of selective or specific chemical and biological detection methods directly to the chromatogram. Disadvantages are that automation is difficult and that the sensitivity and accuracy of the quantitative analysis are slightly lower than for other methods. Both TLC and PC are very closely related in their technical aspects. The techniques of sample application, development, and detection are analogous, as are the techniques of qualitative and quantitative analysis. The two methods differ fundamentally in the nature of the stationary phase. In PC, the stationary phase is in most cases anchored to a carrier in sheet form, that is, on the paper. In TLC, separation ordinarily occurs on a sorbent that is either loosely spread on, or, more often, fixed on a rigid support, usually a glass plate or a foil.