Enhanced fluorescence of the terbium–gadolinium–nucleic acids system and the determination of nucleic acids Original Research Article

It is first found that the fluorescence of Tb–nucleic acids (fish sperm DNA (fsDNA) and yeast RNA (yRNA)) can be increased by Sc3+, Y3+, La3+, Gd3+ and Lu3+, among which Gd3+ and Lu3+ have the greatest enhancement. This is a new co-luminescence system. This system is studied in detail and is applied to determine nucleic acids. The experiments indicated that under the optimum conditions, a linear relationship was obtained between the fluorescence intensity (If) and the concentration of nucleic acids. The linear ranges are 1.0 × 10−8–1.2 × 10−4 g/ml for DNA and 2.5 × 10−8–8.5 × 10−4 g/ml for RNA. The detection limits (signal : noise = 3) for DNA and RNA were 4.3 × 10−9 and 6.4 × 10−9 g/ml, respectively. The mechanism of the co-luminescence effect is also discussed.