The simultaneous assay of riboflavin 5-phosphate sodium and other water-soluble vitamins in liquid multivitamin formulations by liquid chromatograph.

A simple liquid chromatographic method for the simultaneous assay of niacinamide, pyridoxine, thiamine and riboflavin 5'-phosphate sodium in liquid multivitamin formulations is described. A novel aspect of the procedure is the conversion of the riboflavin 5'-phosphate sodium to riboflavin (vitamin B(2)) by reaction with alkaline phosphatase prior to quantitative HPLC. Excellent recovery, linearity and accuracy are obtained by the proposed method.