Direct determination of single-to-double stranded DNA ratio in solution using steady-state fluorescence measurements.

We report a simple and rapid method for quantitation of single-to-double stranded (ss : ds) DNA ratios in solution, using steady-state measurements of fluorescence from two simultaneously excited intercalated dyes; the ratio of fluorescence intensities from PicoGreen (525 nm) and ethidium bromide (610 nm) is directly proportional to the ss : ds DNA ratio.