Studies on the fluorescence reaction between nucleic acid and the complex of cobalt(II) with 5-(3-fluoro-4-chlorophenylazo)-8-sulfonamidoquinoline and its applications

Based on the enhancement of the fluorescence intensity of the complex of 5- (3-fluoro-4-chlorophenylazo)-8-sulfonamidoquinoline (FCPBSQ) with Co2+ by n ucleic acid in the presence of Tween 80 and in the weakly basic medium, a f luorescence method for the determination of nucleic acid was proposed, The calibration graphs for the determination of denatured calf thymus DNA (ct D NA), fish sperm DNA (fs DNA), and yeast RNA (yt RNA) were obtained in conce ntration ranges 0.050-4.0, 0.10-3.0, and 0.050-3.0 mu g/ml with limits of d etection of 0.010, 0.030, and 0.020 mu g/ml, respectively, The method has b een satisfactorily used for the determination of DNA in wheat cell extracti on and ct DNA, fs DNA, and yt RNA in synthetic samples. Investigations on t he binding mode by the Scatchard plots method suggested that both intercala tion and electrostatic binding modes existed in this system. (C) 2000 Acade mic Press.