ABSTRACT
Conventional planar and nonplanar as well as thin-and thick-layer liquid chromatographic techniques require few instruments and are rather simple. Among the planar layer liquid chromatographic techniques, paper chromatography (PC) and its various versions developed in the 1940s by Martin and Synge (1) have to be mentioned first. Thin-layer chromatography (TLC), discovered by Ismailov and Shraiber (2) as well as Békésy (3), improved by Kirchner et al. (4), and standardized and spread by Stahl et al. (5, 6), contributed to the isolation and analysis of many natural and synthetic substances. Today, versions of this classical chromatographic technique are indispensable in various fields of scientific research and practice.
