FLUORESCENCE INVESTIGATION OF THE INTERACTION OF SAFRANINE-T WITH DNA

A fluorescence probe, safranine T (ST), was proposed for the investiga tion of DNA. ST is a fluorescent cationic dye. Its fluorescence intens ity decreased significantly in the presence of DNA. Evidence showed th at the fluorescence quenching was due to the formation of a complex be tween dye and DNA which is less fluorescent than the free dye. Steady- state anisotropy measurements demonstrated that ST bound to DNA and re sulted in an increase in anisotropy. The calibration graphs for the de termination of Calf thymus DNA (CT DNA) and fish sperm DNA (FS DNA) we re obtained. Good linear dependency of F-0/F on the concentration of D NA was observed with the concentration ranging from 8.3 ng/ml to 15.0 mu g/ml for CT DNA and from 14.0 ng / ml to 16.0 mu g / ml for FS DNA. The LOD were 8.3 ng / ml and 14.0 ng / ml for CT DNA and FS DNA, resp ectively. The relative standard deviations were 1.44 % and 0.92 % for 4.0 mu g / ml and 0.40 mu g / ml of CT DNA, respectively, and 1.52% an d 1.12% for 4.0 mu g / ml and 0.50 mu g / ml of FS DNA, respectively.