UNIT 2.1A Purification and Concentration of DNA from Aqueous Solutions

  1. David Moore,
  2. Dennis Dowhan

Published Online: 1 AUG 2002

DOI: 10.1002/0471142727.mb0201as59

Current Protocols in Molecular Biology

Current Protocols in Molecular Biology

How to Cite

Moore, D. and Dowhan, D. 2002. Purification and Concentration of DNA from Aqueous Solutions. Current Protocols in Molecular Biology. 59:I:2.1A:2.1.1–2.1.10.

Author Information

  1. Baylor College of Medicine, Houston, Texas

Publication History

  1. Published Online: 1 AUG 2002
  2. Published Print: JUL 2002


This unit presents basic procedures for manipulating solutions of single- or double-stranded DNA through purification and concentration steps. These techniques are useful when proteins or solute molecules need to be removed from aqueous solutions, or when DNA solutions need to be concentrated. The Basic Protocol, using phenol extraction and ethanol (or isopropanol) precipitation, is appropriate for purification of DNA from small volumes (<0.4 ml) at concentrations lower than 1 mg/ml. Three support protocols outline methods to buffer the phenol used in extractions, concentrate DNA using butanol, and extract residual organic solvents with ether. An alternative to these methods is nucleic acid purification using glass beads and this is also presented. These protocols may also be used for purifying RNA. The final two alternate protocols are used for concentrating RNA and extracting and precipitating DNA from larger volumes and from dilute solutions, and for removing low-molecular-weight oligonucleotides and triphosphates.