A fact of intermolecular reactions or interactions between the liquid crystal and the chromatographed substances is important for the understanding of the phenomena taking place in the chromatographic column. The structure of the molecules and their polarity and polarizability affect, as well as, the solubility of the chromatographed substances in the liquid crystal plays an important influence on the separation. The properties of the liquid crystal stationary phases depend both on the structure of the main chain of the molecule and on the terminal substituents which strongly affect the...

This work was made to study the photochemistry of riboflavin and the kinetics of riboflavin degradation after exposure to UV-Vis light phosphate buffer solution at different pH interval (2-10) with the same concentration (5x10-5M ) was studied by the of UV-Vis spectrophotoscopy analyses, it showed that degradation increase as pH increase from pH (2-7)where the lumichrome a photoderivative forms in the acidic medium. a maximum degradation occurs at neutral pH (7). Then it began to decrease from pH (7-10). Where the lumiflavine (a photoderivative occurs at basic media) formed. We also...