Cooling plate for cellulose thin-layer electrophoresis and its application to amino acid analysis

Abstract

A stainless-steel water-cooled plate has been designed for the electrophoresis of small and intermediate sized molecules on plastic based cellulose thin layers. The upper cooling surface of the plate was formed by milling out five shallow grooves aligned to the direction of electrophoresis. Insulation of the plate was achieved by dipping it in a suspension of electrostatically charged plastic particles. Electrophoresis was carried out by soaking five thin-layer strips in the electrolyte (4%, v/v, formic acid), and laying them with the layer face down along the cooling surface so that the sample spot was sighted over the centre of a groove. Electrophoretic separation then took place along the uncooled zone covering the groove. Adjustment of the electrolyte concentration and the voltage made it possible under these conditions to separate 23 amino acids when developed by chromatography in the second dimension using 15 × 18 cm layers.