Determination of calf thymus DNA using resonance light-scattering quenching method based on the terbium (Ш) (Tb3+)/europium (Ш) (Eu3+)-quercetin system

It is found that at pH 7.5 Tris-HCl buffer solution, calf thymus DNA (ctDNA) can quench the resonance light-scattering (RLS) of terbium (Ш) (Tb3+)/europium (Ш) (Eu3+)-quercetin system. Based on this, a sensitive method for the determination of ctDNA is proposed. The characteristics of RLS spectra, the effective factors and optimal experimental conditions were investigated. Under the optimal conditions, the quenched RLS intensity is in proportion to the concentration of ctDNA. For Tb3+-quercetin-ctDNA system, the linear concentration ranges for determining ctDNA are 0.03-0.2 and 0.5-4 μg/ml, respectively, while for Eu3+-quercetin-ctDNA system, the linear concentration range is 0.05-2.5 μg/ml.