Purification of DNA by Anion‐Exchange Chromatography

Abstract Column chromatography has evolved to provide a rapid and effective alternative to more laborious methods for preparing high‐quality DNA, such as CsCl‐gradient centrifugation. This unit describes the use of a column made of a unique anion‐exchange resin that selectively binds nucleic acids, allowing rapid separation of DNA from contaminating RNA, proteins, carbohydrates, and metabolites. The procedure employs columns supplied by QIAGEN; other preparation methods are available from other suppliers. A crude nucleic acid sample (usually a cleared cell lysate) is applied to the QIAGEN tip under conditions that favor binding. Contaminants in the sample are washed from the column with a moderate‐salt buffer, and DNA is eluted using a high‐salt buffer.