Determination of DNA at Nanogram Levels by Resonance Light Scattering Technique in Organic Acid Medium

Abstract

The different enhancement of resonance light scattering of DNA is observed in formic acid, acetic acid, propionic acid, butyric acid, trichloroacetic acid and trifluoroacetic acid. The results indicated that there was a maximum enhancement of resonance light scattering of DNA at 340 nm in 0.2 mol L^-1 trichloroacetic acid medium. The concentration of calf thymus DNA (ctDNA) in the range of 0.05-50 μg mL^-1 and fish sperm DNA (fsDNA) in the range of 0.05-40 μg mL^-1 is well proportional to the enhanced resonance light scattering intensity. The detection limits are 12.2 ng mL^-1 for ctDNA and 17.9 ng mL^-1 for fsDNA, respectively. Nucleotides at 4 μg mL^-1, proteins at 0.1 μg mL^-1 and most of metal ions at 1.0 × 10^-5 mol L^-1 do not interfere with the determination of DNAs. This method has been applied to the determination of calf thymus DNA and fish sperm DNA in synthesized samples with satisfactory results.