The interaction between epirubicin hydrochloride and DNA such as calf thymus DNA(ct DNA), salmon DNA(sDNA), herring sperm DNA(hsDNA) was studied using resonance Rayleigh scattering (RRS) method. In pH 2.0 acidic medium, the RRS signal of epirubicin or nucleic acid alone was very weak, but it was enhanced greatly and new RRS spectra appeared when they interacted with each other to form a bound product. There was a little difference of RRS spectra of the bound products for a variety of DNA and their increments of RRS intensity were followed by this sequence, ctDNA≈sDNA＞hsDNA. Furthermore the RRS intensity is proportional to the concentration of DNA in a certain range, and so a new method for the determination of DNA with epirubicin by RRS technique was developed. The sensitivity of the method was high with detection limits of different DNA being between 24.0 ng/mL and 28.0 ng/mL and the results of determination of DNA in the synthetic samples with RRS method were satisfactory. The optimum conditions, influence effects and the properties of analytical chemistry of the bound products were also investigated and the reaction mechanism was discussed using RRS associated with absorption and fluorescence spectra.

Key words: resonance Rayleigh scattering, epirubicin hydrochloride, DNA