International Journal of
Physical Sciences

  • Abbreviation: Int. J. Phys. Sci.
  • Language: English
  • ISSN: 1992-1950
  • DOI: 10.5897/IJPS
  • Start Year: 2006
  • Published Articles: 2574

Full Length Research Paper

Spectrophotometric study of the solution interactions between riboflavin, sodium salicylate and caffeine

Bolotin P. A., Baranovsky S. F., Chernyshev D. N. and Evstigneev M. P.*
Department of Physics, Sevastopol National Technical University, Sevastopol, 99053, Crimea, Ukraine.
Email: [email protected]

  •  Accepted: 14 February 2007
  •  Published: 31 March 2007

Abstract

The self-association of Vitamin B2 (Riboflavin, RBF) and its hetero-association with Sodium Salicylate (NAS) and Caffeine (CAF) have been studied in aqueous solution by UV-Vis spectrophotometry. Using modified Benesi-Hildebrand approach equilibrium hetero-association constants were obtained for RBF-NAS [K = (25 ± 4) M-1] and RBF-CAF [K = (69 ± 4) M-1] systems at T = 298K. Absorption spectra of the vitamin in the mixed solutions with CAF/NAS evidence a bathochromic and hyperchromic shifts which are indicative of the hetero-association process between the dissolved molecules, most likely occurring via vertical stacking of their chromophores. Addition of Urea to the solutions of RBF-NAS and RBF-CAF decreases the stability of the hetero-complexes downto K = (17 ± 3) M-1 and K = (51 ± 7)M-1, respectively.

 

Key words: Spectrophotometry, riboflavin, caffeine, nicotinamide, urea, hetero-association