Determination for micro amounts of nucleic acids by a resonance light scattering technique with dequalinium chloride

Based on the strong enhancement effect of nucleic acids on resonance light scattering of dequalinium chloride, the determination method for micro amounts of nucleic acids has been developed. Under the experimental conditions (5.0×10−5 mol l−1 dequalinium, pH 7.0, at room temperature) the linear range of this assay is 0.04–10.0 μg ml−1 for calf thymus DNA and fish sperm DNA, and 0.04–35.0 μg ml−1 for yeast RNA. The detection limits (3σ) are 6.2 ng ml−1 for calf thymus DNA, 7.4 ng ml−1 for fish sperm DNA, and 7.0 ng ml−1 for yeast RNA, respectively. Almost no interference can be observed from ionic strength, proteins, nucleoside, and most of the metal ions. Six synthetic samples were determined satisfactorily.