Abstract
The authors studied on the cup method for the determination of cyano- and hydroxocobalamin. An agar layer containing 0.13% of 2,3,5-triphenyltetrazolium chloride was poured on the flat surface of the agar layer containing nutrient medium and cell suspension of Lactobacillus leichmannii. After the incubation for 18〜20 hours at 37℃, diameters of the red coloured growth zones of lactobacilli around the cups were measured. Thus, the determination of cyano- and hydroxocobalamin in pure solution were successfully performed in the range of 50〜1000mμg/ml with a little errors, but with regard to the natural product further examination would be necessary.
