The preparation of silica gel thin layers with a new apparatus.

An apparatus for the preparation of uniform thin layer chromatography gel layers is described. The apparatus employs rubber cushion runners to compensate for differences in plate thickness and a gel applicator which functions independently of plate edge variability. Consistently uniform layers are prepared by careful establishment of the plate-to-applicator distance. Silica gel layers averaged 87% of the applied thickness with a variability of +/-2% within a single run and +/-8% between independent runs.