Determination of nucleic acids with Crystal Violet by a resonance light-scattering technique

Abstract

For the first time, Crystal Violet (CV) was used to determine nucleic acid concentrations using the resonance light-scattering (RLS) technique. Based on the enhancement of the RLS of CV by nucleic acids, a new quantitative determination method for nucleic acids in aqueous solutions has been developed. At pH 5.03 and ionic strength 0.005 mol kg⁻¹, the interaction of CV with nucleic acids results in three characteristic RLS peaks at 344.0, 483.0 and 666.0 nm. With 4.0 × 10⁻⁵ mol l⁻¹ of CV, linear relationships were found between the enhanced intensity of RLS at 666.0 nm and the concentration of nucleic acids in the range 0–2.5 µg ml⁻¹ for herring sperm DNA, 0–4.0 µg ml⁻¹ for calf thymus DNA and 0–4.5 µg ml⁻¹ for yeast RNA. The limits of determination were 13.8 ng ml⁻¹ for herring sperm DNA, 36.8 ng ml⁻¹ for calf thymus DNA and 69.0 ng ml⁻¹ for yeast RNA. The assay is convenient, rapid, inexpensive and simple.