A new preparative thin-layer chromatographic technique for using thicker layers

Abstract

A method has been developed for the production and development of thick layers ranging from 1 8 in. to 1 2 in. thick. These layers do not have a supporting back plate, but are contained within a stainless-steel framework with thin stainless-steel wires stretched across the frame to help support the adsorbent layer. In this manner both surfaces of the plate are available for application of the sample and for the observation of separated zones. The layers were formed of silica gel with 20% gypsum binder based on the weight of the silica gel. A special chamber was constructed for development of the layers. The method was demostrated by the separation of a number of dyes. In contrast to running numerous thin-layer plates to obtain preparative amounts of colorless compounds, the thick layers provide a means for spraying the surface with a visualizing reagent, and then removing the thin surface layer once the zones are located and still leave adequate amounts of the unsprayed compounds for recovery.