Spectrofluorimetric determination of nucleic acids as 8-hydroxyquinoline/ yttrium ternary complexes

The formation of nucleic acids/8-hydroxyquinoline/yttrium(III) ternary complexes and their fluorescent properties have been studied. The nucleic acids studied include native and thermally denatured calf thymus DNA, fish sperm DNA and yeast RNA. In the range of pH 7.6–8.5, controlled by NH3-NH4C1 buffer, ternary complexes are formed that fluoresce at different wavelengths with different nucleic acids. Based on the fluorescence reactions, sensitive spectrofluorimetric methods for nucleic acids are proposed. In optimal conditions, the calibration curves were linear in the range 0.5–4.0 μgml−1 for calf thymus DNA, 0.5–2.5 μg ml–1 for fish sperm DNA and 0.5–4.0 μg ml–1 for yeast RNA. The limits of determination (3 σ) were 0.030 μg ml−1 for calf thymus DNA, 0.020 μg ml−1 for fish sperm DNA and 0.090 μg ml−1 for yeast RNA. Corresponding to the interferences of coexisting substances, six synthetic samples were constructed and the results of determination were satisfactory.