Abstract
No marked difference in adsorption of vitamin B_<12> was found between Amberlite IR C-50 and carbon impregnated IRC-50. The former resin was used to purify vitamin B_<12>. The optimum pH for adsorption ranged from 1.5 to 3.0 (ordinarily 2.5), 0.1 N HCl solution in 75% acetone or 50% isopropyl alcohol was used as an eluting agent. When sample solution of vitamin B_<12> contained much impurities, adsorption of the vitamin was greatly obstructed and for elution a large amount of solvent was necessary. With partially purified sample solution, adsorption took place quickly and less amount of solvent was repuired, but purification was not improved thereby. In the latter case, however, chromatographic seperation succeeded more satisfactorily.
