caa a22 4500 44532872X CHVBK 20180317142730.0 cr unu---uuuuu 170323e20110201xx s 000 0 eng 10.1007/s10953-010-9643-5 doi (NATIONALLICENCE)springer-10.1007/s10953-010-9643-5 Spectrofluorimetric Studies of the Interaction Between Quinine Sulfate and Riboflavin [Elektronische Daten] [D. Patil, S. Bhattar, G. Kolekar, S. Patil] The molecular interaction between quinine sulfate [QS] and riboflavin [RF] was investigated by fluorescence and UV-VIS absorption spectroscopy in aqueous solutions. The fluorescence of QS was quenched by RF. The Stern-Volmer quenching equation was successfully applied and the corresponding thermodynamic parameters enthalpy change (ΔH), Gibbs energy change (ΔG) and entropy change (ΔS) were calculated at different temperatures (294, 301, 307 and 314 K) according to the van't Hoff equation. This information showed that hydrogen bonds play a major role in stabilizing the complex. The value of the critical energy transfer distance (R 0) was found to be 46.47 Å, less than 50 Å, which proves that an efficient resonance energy transfer takes place between QS (donor) and RF (acceptor). The oxidation and reduction potentials determined from cyclic voltammetry indicated that association of QS and RF occurs in the excited state by electron transfer. The fluorescence quenching method was successfully applied for the direct determination of riboflavin (vitamin B2) from pharmaceutical samples. Springer Science+Business Media, LLC, 2011 Fluorescence quenching nationallicence Quinine sulfate nationallicence Riboflavin nationallicence Thermodynamic parameters nationallicence Cyclic voltammetry nationallicence Patil D. Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, 416 004, Kolhapur, Maharashtra, India aut Bhattar S. Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, 416 004, Kolhapur, Maharashtra, India aut Kolekar G. Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, 416 004, Kolhapur, Maharashtra, India aut Patil S. Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, 416 004, Kolhapur, Maharashtra, India aut Journal of Solution Chemistry Springer US; http://www.springer-ny.com 40/2(2011-02-01), 211-223 0095-9782 40:2<211 2011 40 10953 https://doi.org/10.1007/s10953-010-9643-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10953-010-9643-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Patil D. Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, 416 004, Kolhapur, Maharashtra, India aut NATIONALLICENCE 700 1- Bhattar S. Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, 416 004, Kolhapur, Maharashtra, India aut NATIONALLICENCE 700 1- Kolekar G. Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, 416 004, Kolhapur, Maharashtra, India aut NATIONALLICENCE 700 1- Patil S. Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, 416 004, Kolhapur, Maharashtra, India aut NATIONALLICENCE 773 0- Journal of Solution Chemistry Springer US; http://www.springer-ny.com 40/2(2011-02-01), 211-223 0095-9782 40:2<211 2011 40 10953 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer