The selectivities of TLC systems were compared by use of correlations between RF(II) and RF(I) (by analogy with two-dimensional TLC). The greatest spread of points, indicative of individual selectivity, was obtained for nonaqueous mobile phases on silica and aqueous mobile phases on octadecyl silica adsorbent wettable with water (RP-18 W). The correlation of RF values in normal- and reversed-phase systems was utilized in the practical separation of a mixture of 14 triazines and urea herbicides using two-dimensional thin-layer chromatography on a Multi-K CS5 dual phase (3 cm strip of octadecyl silica parallel to silica layer). The plate was videoscanned showing the real picture of the plate.
Chromatography, Thin Layer Herbicides