A study of the binding of C.I. Mordant Red 3 with bovine serum albumin using fluorescence spectroscopy

The interaction of C.I. Mordant Red 3 and bovine serum albumin was investigated using fluorescence and UV–vis absorption spectroscopy. Fluorescence quenching, from which binding parameters were evaluated, revealed that the quenching of the serum by C.I. Mordant Red 3 resulted from the formation of a dye–serum complex. The enthalpy and entropy changes for the reaction were −50.49 kJ mol−1 and −50.88 J mol−1 K−1 respectively. van der Waals forces and hydrogen bonds were the dominant intermolecular forces that stabilize the complex; the distance between donor and acceptor was 2.79 nm, according to Förster's non-radiative energy transfer theory. The effect of the dye upon the conformation of bovine serum albumin was analyzed using synchronous fluorescence spectrum.