Automated determination of DNA using the fluorochrome Hoechst 33258.

An automated method for the determination of DNA content in fractions from the alkaline filter elution assay of DNA damage has been developed. DNA-containing fractions are mixed with a fluorochrome (Hoechst 33258) and the DNA concentration is measured fluorometrically in a continuous-flow system. The lower limit of detection is 0.05 micrograms DNA/ml, and the linearity range under the conditions used is 0-8 micrograms DNA/ml. The standard deviation (n = 10) was found to be +/- 0.83%. The results are compared with the manual method.