Dissolved oxygen alteration of the spectrophotometric analysis and quantification of nucleic acid solutions

Nucleic acids are routinely and readily analysed using the A(260)/A(280) ratio, although this method is known to be prone to erroneous results owing to contaminants in solution that absorb at similar wavelengths. The aim of the present review, while highlighting the problems and alternatives of using UV spectrophotometry for nucleic acid measurements, is to bring forth an observational result from our recent studies, namely that DO (dissolved oxygen) and nitrogen can alter the A(260) of aqueous DNA solutions. Our finding is of importance because DO is highly variable between protocols and storage conditions of DNA preparations. The physicochemical nature of the oxygen-DNA interactions is briefly discussed.