Device for the recognition of the solvent front in chromatography and sensor therefor

A device for the recognition of the solvent front in chromatography, especially in thin-layer chromatography, having a holder for a plate which can be immersed in a development chamber, as well as a sensor assigned to the latter, is intended to allow the recognition, independent of time, of the attainment of the desired solvent distance without disturbance and reproducibly. For this purpose, the sensor/s (30) is/are arranged at a small distance (a) from the plate (20) on the holder (22) and provided with the plate in the development chamber (18). In addition, a plurality of spaced apart plates (20) are preferably installed so as to be detachable in a clamping device (24) of the holder (22). The sensor (30) suitable therefor has at least one optical reflection detector (32), which is embedded in a material which is resistant to solvent.