Chromatographic and spectroscopic investigation of 'irreversible adsorption' in the course of multiple development in conventional TLC and HPTLC and in OPLC

Multiple development is widely used for improving the resolution of planar chromatographic methods, Despite its advantageous features, multiple develo pment cannot be generally used, because occasionally artefact spots can be observed as a consequence either of irreversible adsorption or of degradati on of the analytes chromatographed, Is this work the origin and the possibilities of elimination of irreversibl e adsorption during multiple development are investigated and discussed, Th e analytical methods employed were conventional TLC and HPTLC, personal OPL C, gas chromatography, nuclear magnetic resonance spectroscopy, and mass sp ectrometry.