Rayleigh light scattering study on the reaction of nucleic acids and methyl violet.

A new quantitative determination method for nucleic acids in aqueous solutions, based on the enhancement of Rayleigh light scattering of methyl violet by nucleic acids, has been developed. The sensitivity of the assay allows amounts of nucleic acids as little as 100 ng/ml to be quantitated reliably. In addition to its high sensitivity, this method has other advantages: rapidity of reaction (<5 min), simplicity of operation (one-step assay), commonality of spectrofluorimeter and reagents, stability of mixtures formed, and reproducibility. Under the experimental conditions, there is little or no interference from proteins, nucleosides, and most metal ions. Interference by a few metal ions, detergents, and some salts can be minimized by dilution. The method can also be used to determine the total amount of nucleic acids without the arduous choice of standard and difficult separation of DNA and RNA.