A novel planar liquid chromatographic technique using a pressurized ultramicro chamber (PUM chamber) has been developed. The sorbent layer is completely covered by a membrane under external pressure, so that the vapour phase above the layer is virtually eliminated. Solvent is admitted under pressure by means of a pump system. The main advantage of this technique, termed overpressured thin-layer chromatography (TLC), is the substantially shorter time required for separation than in classical column chromatography and TLC, with velocities of the mobile phase about as stable as in high-performance liquid chromatography, and aggressive reagents being applicable as in classical TLC. The method appears to be suitable for the accurate modelling of column chromatographic methods. © 1979.
