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

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 de termination method for nucleic acids in aqueous solutions has been develope d. At pH 5.03 and ionic strength 0.005 mol kg(-1), the interaction of CV wi th nucleic acids results in three characteristic RLS peaks at 344.0, 483.0 and 666.0 nm. With 4.0 x 10(-5) mol l(-1) of CV, linear relationships were found between the enhanced intensity of RLS at 666.0 nm and the concentrati on of nucleic acids in the range 0-2.5 mug ml(-1) for herring sperm DNA, 0- 4.0 mug ml(-1) for calf thymus DNA and 0-4.5 mug 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 c onvenient, rapid, inexpensive and simple.