Vapor-programmed thin-layer chromatography, a technique for improved separations

Influence of chamber saturation in thin‐layer chromatography on theoretical and experimental parameters of mixture separations

“…II. The chamber according to de Zeeuw [6,7] in which the space over the layer of adsorbent is saturated with vapours of pure or mixed solvent. If chromatogram was developed with mixed solvent, the adsorbent layer was saturated with vapours of the same solvent of the same concentration of the vapoursthe adsorbent layer was fixed at a distance of 2 mm from the solvent of the same concentration as that used for the development of the chromatogram.…”

“…V. An unsaturated chamber [2][3][4]6,7] in which solvent vapours are partially removed through a slit made by opening the cover slightly.…”

“…The type of adsorbent and its activity, as well as activity of the solvent used as the mobile phase, are regarded as the most important parameters. It was proved by de Zeeuw [6,7] that the composition of the vapour of the solvent in the development chamber plays a very significant role in thin-layer chromatography. The role of demixing of a multicomponent solvent on the reproducibility of TLC chromatographic parameters had already been observed by Srahl [2-41, and later it was extensively studied by Evaporation ofthesolvent andthe liquid-vapourequilibrium significantly affects the reproducibility of the thin-layer chromatography results, since the adsorbent layer on the plate is able to adsorb vapours from the gaseous phase.…”

“…The common opinion [6] is that there are no frontal effects in unsaturated chambers and thus a better separation of mixtures. In this technique the plate is inserted into the chamber just after the solvent has been poured in so that, at the beginning of chromatogram development, the concentration of solvent vapours is much less than at the point of saturation.…”

Gas-liquid chromatography of derivatized barbiturates: An undergraduate experiment

“…On leave from Department of Physical Chemistry, University of Leeds, England 2. From Supelco, Inc., Bellefonte, Pa.…”