Langmuir Aggregation of Thionin in Nucleic Acids and Its Application

The microsurface adsorption‐spectral correction (MSASC) technique has been described. The formation of the double electrostatic films in nucleic acids causes the monolayer aggregation of stain molecules. The interaction of thionin (TN) with nucleic acids, ctD‐NA, sDNA and yRNA, has been investigated at pH 7.8. Results show that the binding ratios of TN to ctDNA‐P, sDNA‐P and yR‐NA‐P are 1.27, 1.30 and 1.40, respectively, the binding constants of the aggregates are 2.8 · 10 4 , 9.10 · 10 4 and 6.49 · 10 3 and their molar absorptivities are 1.04 · 10 4 , 1.25 · 10 4 and · 10 4 L· mol −1 , cm −1 at 630 nm. The aggregation may be applied to the spectrophotometric detection of nucleic acids samples.