Voltammetric Behavior of Certain Vitamins and Their Determination in Surfactant Media

The behavior of riboflavin and L - ascorbic acid in surfactant media has been studied by cyclic voltammetry at a carbon paste electrode. The surfactants employed were certain ionic and a nonionic, viz., cetyltrimethyl ammonium bromide, cetylpyridinium chloride, sodiumdodecyl sulfate, and TritonX 100. The redox potentials of the vitamins were found to be different in different surfactants. The presence of cationic surfactants showed a shift in the peak potentials and peak currents of the vitamins. The presence of anionic surfactant, caused an increase in the peak currents of riboflavin without any change in peak potentials whereas no such effect was observed for ascorbic acid. The enhancement in the sensitivity of the carbon paste electrode towards riboflavin was made use of to determine the limit of detection and linear concentration range by the differential pulse voltammetric technique. Simultaneous determination of riboflavin and ascorbic acid was carried out. Multivitamin-multimineral pharmaceutical preparations analyzed gave satisfactory results.