Simple and sensitive determination of nucleic acid by Rayleigh light scattering technique with methyl green-CTMAB

A method is presented for the determination of nucleic acid, based on the e nhancement of Rayleigh light scattering (RLS) of methyl green (MG)-CTMAB in the pH range 6.9-7.2 at 414.0 nm. The enhanced intensity of RLS is proport ional to the concentration of nucleic acid in the range 2.5x10(-8)-2.0x10(- 6) g/ml for calf thymus (ct)DNA, 2.5x10(-8)-2.0x10(-6) g/ml for fish sperm (fs)DNA, 7.5x10(8)-2.0x10(-6) g/ml for yeast (y)RNA. The detection limits ( 3 sigma) are 7.8, 2.6, 9.9 ng/ml for ctDNA, fsDNA and yRNA respectively. Be sides its high sensitivity, it has some other advantages: simplicity of ope ration, commonality of spectrometer and reagents, good stability of chemica l system and reproducibility. The procedure has been successfully applied t o the determination of nucleic acid in synthetic samples.