HPLC/MS Analysis of Riboflavin Sodium Phosphate Consisting of Several Structural Isomers Together with Thiamine HCL, Pyridoxine HCL, Dexpanthenol, and Nicotinamide in A Multi-Vitamin Injection Solution

We were tasked with testing a multicomponent aqueous solution for injection used in medicine. The composition of the solution included the following components: Riboflavin sodium phosphate (vitamin B2), Thiamine HCl (vitamin B1), Pyridoxine HCl (vitamin B), Dexpanthenol (vitamin B5), and Nicotinamide (vitamin B3), also benzyl alcohol. The complexity of the simultaneous determination of these components was that they differ in their acid-base properties, physical-chemical properties, concentration in solution, and solubility in the mobile phase. The key to solving this task is the correct choice of method for analyzing riboflavin sodium phosphate in each vitamin mixture. Riboflavin is taking particular attention because this component has a few isomers that are separated by HPLC.