Quercetin-La(III) complex for the fluorimetric determination of nucleic acids

The ternary fluorescent complexes of nucleic acids-quercetin-lanthanum(III) were studied. Nucleic acids in this study involve natural and thermally de natured calf thymus DNA (ctDNA), yeast DNA (yDNA) and yeast RNA (yRNA). In the pH range 7.8-8.3 (controlled by NH3-NH4Cl buffer) ternary fluorescent c omplexes are formed which give maximum emission at 470 nm when excited at 2 80 nm. Based on the fluorescence reactions sensitive fluorimetric methods f or nucleic acids were proposed. Using optimal conditions, the calibration c urves were linear in the range of 0.5-3.0 mu g ml(-1) for ctDNA, 0.5-4.0 mu g ml(-1) for yDNA and yRNA. The limits of determination (3 sigma) were 0.0 72 mu g ml(-1) for ctDNA, 0.142 mu g ml(-1) for yDNA and 0.307 mu g ml(-1) for yRNA, respectively. Six synthetic samples were determined with satisfac tion. (C) 1999 Published by Elsevier Science B.V. All rights reserved.