Ethanol Precipitation of Plasmid DNA

Reagents Needed:
• 3 M sodium acetate pH 5.2 or 5 M ammonium acetate
• DNA
• 100% ethanol
Protocol
1. Measure the volume of the DNA sample.
2. Add 1/10 volume of sodium acetate, pH 5.2, (final concentration of 0.3 M)
 - These amounts assume that the DNA is in TE only; if DNA is in a
 solution containing salt, adjust salt accordingly to achieve
 the correct final concentration.
3. Mix well.
4. Add 2 to 2.5 volumes of cold 100% ethanol (calculated after salt addition). (or 0.6 vol of isopropanol)
5. Mix well.
6. Place on ice or at -20 degrees C for >20 minutes.
7. Spin a maximum speed in a microfuge 10-15 min.
8. Carefully decant supernatant.
9. Add 1 ml 70% ethanol. Mix. Spin briefly. Carefully decant supernatant.
10. Air dry or briefly vacuum dry pellet.
11. Resuspend pellet in the appropriate volume of TE or water.