“…Numerous techniques for identifying the 2,4dinitrophenyl (DNP)-derivatives have been reported (I), including paper chromatography, column chromatography, paper electrophoresis, and countercurrent distribution. Column chromatography of the DNP-derivatives employing a variety of supporting materials, such as silica gel (1, 11¡), Kieselguhr (10), Celite (9,11,12), silicic acid-Celite (8,16), ion exchange resin (18), and nylon powder (4,20) has met with variable success.…”