[Determination of deoxyribonucleic acids based on the enhanced effect of resonance light scattering of malachite green sensitized by cetyltrimethylammonium bromide].

A resonance light scattering (RLS) enhancement method was reported for the determination of deoxyribonucleic acids. The proposed method was based on the enhanced effect of deoxyribonucleic acid on the resonance light scattering of malachite green (MG) sensitized by cetyltrimethylammonium bromide (CTMAB). Alkaline medium was necessary for the experiment. Under optimal conditions, the linear ranges for both calf thymus DNA (ctDNA) and fish sperm DNA (fsDNA) were 0-1.5 microg x mL(-1), the detection limits were 0.05 microg x mL(-1) for ctDNA and 0.03 microg x mL(-1) for fsDNA. The measurement can be made on normal spectrofluorimeter. Mechanic studies show that MG probably aggregates on the molecular surface of single-chained DNA, and then interacts on CTMAB to form large particles, which produce strong RLS. This method was successfully applied to the determination of DNA in synthetic samples.