To precipitate DNA, add 1/10 volume of 3M sodium acetate (NaOAc)( pH 5.2) plus 2-3 volumes of cold 100% ethanol (ETOH) to the solution containing DNA. One volume is the volume of the solution containing the DNA.

Example: to precipitate a 60 µl solution of DNA, add 6 µl of 3M NaOAc (pH 5.2) and 120-180 µl of cold 100% ETOH.

The solution is then placed at —20^oC for at least 2 hours (often it is left overnight). Alternatively, the solution can be placed at —70^oC for 15 minutes but in my experience this always results in a lower yield.

Finally the solution is centrifuged at 14,00O RPM for 10-20 minutes at 4^oC. The ETOH is removed and the pellet is rinsed once with 70% ETOH. The washed pellet is centrifuged again for 5 minutes at 14K RPM and 4^oC. The ETOH is removed and the pellet is air-dried or dried in a speed vacuum. If air-drying is done, it is best to "pop" spin the pellet after the removal of the 70% ETOH so that any remaining ETOH can be removed.

After drying the pellet can be stored dry or re-suspended for use.