SEPARATION OF OPIUM-ALKALOIDS BY THIN-LAYER CHROMATOGRAPHY COMBINED WITH FLAME IONIZATION DETECTION USING THE PEAK PYROLYSIS METHOD

A fast, efficient and reproducible method for the separation of the five major opium alkaloids by thin-layer chromatography coupled to flame ionization detection is reported. The alkaloids were separated without derivatization on silica rods of type SII using the partial scanning or peak pyrolysis method -where organic matter separated on the rods are burnt when they pass through the hydrogen flame-between the stages of a two-step development system. The first development, in benzene-acetonitrile-ethyl acetate (60:20:20, v/v) separated narcotine and papaverine. Morphine, codeine and thebaine were separated during the second development in ethyl acetate-benzene-acetonitrile-ammonium hydroxide (25:30:40:5, v/v). The best binary solvent system was benzene-ethanol (9.5:0.5, v/v) and (9:1, v/v) which separated all the five alkaloids simultaneously.