Multicomponent spectrophotometric assay of cyanocobalamin, hydroxocobalamin and riboflavin.

The photolysis of cyanacobalamin to hydroxocobalamin in aqueous solution is influenced by riboflavin. A multicomponent spcctrophotometric method has been developed for the simultaneous determination of cyanocobalamin, hydroxocobalamin and riboflavin in degraded solutions by absorbance measurements at 550, 525 and 445 nm. The relative standard deviation of the method is 2,5% and the recoveries range from 97.3-103.3%. The method has been applied to study the photolysis of cyanocobalamin in presence of riboflavin.