Cellulose adsorbents for column chromatography. Residue on ignition <10000 ppm, <20 ppm Fe, <5 ppm Cu, <7 ppm P, dichloromethane extract <0. 20 %. Residue on ignition <1000 ppm, <2 ppm Fe, <1 ppm Cu, <2 ppm P, dichloromethane extract <0. 15 %.