STANDARDIZATION OF THE THIN-LAYER CHROMATOGRAPHIC-SEPARATION OF LICHEN ACIDS FOR THE CHEMOTAXONOMY OF LICHENS

The thin-layer chromatography of lichen extracts for taxonomic studies has been optimized in relation to separation and to reproducibility. Especially good separations were found with benzene:dioxane:acetic acid (90:25:4) developer and silica gel thin-layer plates, whose activity was fixed by an ambient moisture content of 70%, and with methylene chloride developer and silica gel plates impregnated with oxalic acid and antiparallel activity gradient. High reproducibility of separation was obtained using the Geiss Vario-KS tank, which allows the activity of the plates or the activity gradient to be adjusted and which also allows reproducible exposure of plates to the vapour of developing solvents. By different chromatographic separations of the same extracts and by using different colour reactions the accuracy of identification for taxonomic studies has been improved. © 1979 Friedr. Vieweg & Sohn Verlagsgesellschaft mbH.