Sensitive determination of DNA based on the interaction between prulifloxacin-terbium(III) complex and DNA

A simple spectrofluorimetric method is described for the determination of DNA, based on its enhancement of the fluorescence intensity of prulifloxacin (PUFX)-Tb3+. The luminescence intensity of the PUFX-Tb3+ complex increased up to 10-fold after adding DNA. The excitation and emission wavelengths were 345 and 545nm, respectively. Under optimum conditions, variations in the fluorescence intensity showed a good linear relationship with the concentration of hsDNA in the range of 3.0x10(-9) to 1.0x10(-6)g/mL, with a correlation coefficient (R) of 0.997, and the detection limit was 2.1x10(-9)g/mL. The method was successfully applied to the determination of DNA in synthetic samples, and recoveries were in the range 97.3-102.0%. The mechanism of fluorescence enhancement of the PUFX-Tb3+ complex by DNA is also discussed. The mechanism may involve formation of a ternary complex mainly by intercalation binding together with weak electrostatic interaction, which will increase the energy transition from ligand to Tb3+, increasing the rigidity of the complex, and decreasing the radiationless energy loss through O-H vibration of the H2O molecule in the PUFX-Tb3+ compl+osed method is not only more robust and friendly to the environment, but also of relatively higher sensitivity. Copyright (c) 2013 John Wiley & Sons, Ltd.