Simple chamber for temperature-controlled planar chromatography

This article describes a construction of a simple developing device designed for temperature control of thin-layer chromatographic plates. The plates can be developed by the ascending technique under temperature gradient or non-gradient conditions. Saturated or unsaturated chamber conditions can be easily selected. The effects that give rise to pseudo-non-linear Van’t Hoff plots, e.g. a temperature irregularity inside the chamber or heat evolving during solvent adsorption near the migrating front of the mobile phase are minimized. The preliminary temperature–retention studies show that the device is suitable for temperatures ranging from −20 to 60 °C. Using a binary mobile phase mixture (methanol–water, 70:30, v/v) the velocity of the mobile phase front on the HPTLC RP-18W plates at different temperatures was investigated. Under these conditions the retention profiles of four natural estrogens (estetrol, estriol, 17β-estradiol and estrone) were examined. The application of the described device for temperature–retention studies is also discussed.