Multicomponent spectrometric assay of cyanocobalamin and its photoproduct hydroxocobalamin in the presence of ascorbic acid in photolyzed solutions

The simultaneous determination of cyanocobalamin [CC], hydroxocobalamin [HC] and ascorbic acid [AA] in aqueous solution has been achieved by a multicomponent spectrometric method. CC undergoes photolysis in acidic and alkaline media to form HC and the reaction is enhanced in the presence of AA. The method has been used to evaluate the kinetics of photodegradation reactions of the vitamin. CC, HC and AA present in the photolyzed solutions have been determined by absorbance measurement at 550, 525 and 265 nm at pH 4.0. These wavelengths correspond to the absorption maxima of the three substances and thus provide high specificity and sensitivity to the method. The method has been validated with respect to various parameters relating to the analytical performance characteristics. The recovery of the method for the three compounds ranges from 97.1-103.0% with a RSD value of +/- 3%. The accuracy of the method is shown by the linearity of the kinetic plots in the concentration range studied. The method is simple, rapid and convenient for the proposed work

Computational study on the geometry optimization and excited - state properties of riboflavin by arguslab 4.0.1

Riboflavin [vitamin B[2]] belongs to a group of respiratory enzymes that occur widely in animals and plants participating in vital oxidation- reduction processes in the body. A computational study was conducted on riboflavin by ArgusLab 4.0.1 to obtain the most active conformation of riboflavin and to analyze its excited-state properties. The best conformation of riboflavin was found to be -199.2173 kcal/mol which is the minimum potential energy calculated by geometry convergence function by ArgusLab software; performed according to Hartree-Fock calculation method. Electronic transition states [ground and excited], were also calculated and visualized by semi-empirical ZINDO method by ArgusLab from which molecular properties such as energies, wave function and dipole moments were established. All the results obtained from geometry optimization and excited-state properties lead us to delineate the active sites with charged groups of riboflavin to interact with the receptors. Such types of investigations are significant for drug -receptor interactions