Simultaneous Voltammetric Determination of Riboflavin and l-Ascorbic Acid in Multivitamin Pharmaceutical Preparations

Abstract A method for the determination of the riboflavin (Vitamin B2) and l-ascorbic acid (Vitamin C) in pharmaceutical preparations by voltammetry is described. The electrochemical behaviour of riboflavin and l-ascorbic acid in KH2PO4/Na2HPO4 buffer (pH = 6.8) was investigated using glassy carbon electrode. An anodic scan gave peaks at −0.47 V and +0.35 V vs. SCE for riboflavin and l-ascorbic acid, respectively. The oxidation peaks currents are linearly dependent on the concentration of vitamins. Both vitamins can be simultaneously determined from the same voltamogram. RF can be determined in the concentration range 1.5 × 10−6–3 × 10−5 M, however l-ascorbic acid in the concentration range 1.5 × 10−4–3 × 10−3 M. The method proposed for the determination of riboflavin and l-ascorbic acid in multivitamin tablets is very simple, rapid and does not involve time-consuming separation steps.