抄録
Estimation of vitamin B_<12> and total solids in the eluates obtained by the treatment of carbon cake on which the vitamin was adsorbed, with various concentrations of acetone showed that vitamin B_<12> was not eluted with acetone of concentrations less than 20 % while a considerable amount of impurities was removed by acetone of the same concentrations. Consequently, washing of the carbon cake with 15-20 % acetone and elution with 50-60 % acetone afforded to purify the original solution obtained from activated sludge approximately 20-25 fold.
