A new fluorometric method for RNA and DNA determination

Previous studies have shown that a dye, ethidium bromide, markedly increases its fluorescence when it binds to double-stranded DNA or double-stranded regions of RNA. It is shown that, in the given conditions, a linear relationship between fluorescence and nucleic acid concentration is obtained. Thus, a new spectrofluorometric method for determining DNA and RNA using this principle is described. This method is specific for nucleic acids, can be used over a wide range of salt concentrations, and has a good sensitivity (0.01 μg/ml of DNA). No biological compounds able to interfere have been found. An adaptation of this method for determining both DNA and RNA in a mixture is also described.