2001 Volume 17 Issue 6 Pages 693-696
A simple assay of DNA was developed based on the measurements of enhanced signals of Resonance Light Scattering (RLS) of cetyltrimethylammonium bromide (CTMAB) by DNA. The enhanced RLS signals, measured by simultaneously scanning the excitation and emission monochromators of a common spectrofluorometer with λex = λem, was optimized for the DNA assay with CTMAB. On the conditions of pH 2.21 and ionic strength 0.002, the enhanced RLS intensity at 470.0 nm, ΔI, was found to be proportional to the concentration of DNA in the range 0 - 2.5 μg/ml if 1.5 × 10-5 M CTMAB was used. Limits of determination for calf thymus DNA and fish sperm DNA were 4.9 ng/ml and 9.2 ng/ml, respectively. Synthetic samples were determined with the recovery ratio ranging from 93.2% to 105.1%, and the RSD is lower than 2.7%.