A modified fluorometric method for the determination of microgram quantities of DNA from cell or tissue cultures

Incubation of up to 8 μg of DNA with 30 mg DABA at 60°C for 30 min are the optimal conditions for development of fluorescence with DNA. At lower levels of DABA the time of incubation became crucial, and linearity at low DNA concentrations was lost. Application of the method to the estimation of DNA extracted with either 1 n KOH or 1 n PCA from monolayer cell cultures showed that fluorescence could still be developed satisfactorily in the presence of the alkali or acid without neutralizing or drying the sample, thus saving considerable time with no loss of accuracy or reproducibility of the assay, but with some loss of sensitivity.