Effect of multiple development techniques on the chromatographic parameters and separation selectivity of some alkaloids on C18 and CN-silica layers

The retention behavior of selected alkaloids on C18 and CN stationary phases in different eluent systems — mixtures of methanol and water with addition of buffers, acetic acid, ammonia, 1-octanesulfonic acid sodium salt, or diethylamine — has been determined. The separation of weak organic bases such as alkaloids is difficult because of their partial ionization in aqueous solutions. Improvement of separation selectivity, spot shapes, and system efficiency by use of special development methods: unidimensional multiple development (UMD), incremental multiple development (IMD), gradient multiple development (GMD), bivariant multiple development (BMD), and two-dimensional thin-layer chromatography (2D-TLC) was obtained. The effect of applied special development methods on chromatographic parameters obtained for investigated alkaloids in eluents of various composition on two layers was examined.