The sensitive determination of nucleic acids using resonance light scattering quenching method

It is found that in hexamethylene tetramine (HMTA)-HCl buffer of pH 7.00, nucleic acids can quench the resonance light scattering (RLS) of europium (III) (Eu3+)-2-thenoyltrifluoroacetne (TTA)-1,10-phenanthroline (Phen) system. Based on this, a sensitive method for the determination of nucleic acids is proposed. The experiments indicate that under the optimum conditions, the quenched RLS intensity is in proportion to the concentration of nucleic acids in the range of 1.0 × 10−10 to 2.0 × 10−6 g ml−1 for fish sperm (fsDNA), 1.0 × 10−11 to 1.0 × 10−6 g ml−1 for yeast RNA (yRNA), 5.0 × 10−11 to 5.0 × 10−7 g ml−1 for calf thymus DNA (ctDNA). Their detection limits (S/N = 3) are 0.03, 0.006 and 0.002 ng ml−1, respectively. Therefore, the proposed method is the most sensitive RLS method for the determination of nucleic acids so far. The interaction between nucleic acids and Eu3+-TTA-Phen is also discussed.