Automated multiple development thin layer chromatography of some plant extracts

The separation of ten plant extracts using automated multiple development thin-layer chromatography (AMD-TLC) is described. Alcoholic extracts were obtained from Cinchona succirubra, Aesculus hippocastanum, Berberis vulgaris, Artemisia abrotanum, Carduus marianus, Thuja occidentalis, Baptisia tinctoria, Paulinia cupana, Lycopus europaeus and Echinacea angustifolia. The separation was performed on silica plates (Sil G-50 UV 254 (Macherey—Nagel), 10 × 20 cm). AMD was achieved in 25 steps using methanol, ethyl acetate, toluene, 1,2-dichloroethane, 25% ammonia solution and anhydrous formic acid as modifiers. The chromatograms were evaluated with a Shimadzu CS-9000 dual-wavelength flying-spot scanner. Better separations were obtained using AMD than isocratic elution.