Ethanol precipitation of DNA (General protocol)
Ethanol precipitation is used to concentrate or purify DNA. Beware that the pellet
is often very small and barely visible. Be very careful when aspirating to avoid
losing the pellet.
1. Add 1/10th volume 3M sodium acetate pH 5.5. Mix by inverting tube.
2. Add 2-3 volumes of 95-100% ethanol. Mix by inverting tube.
3. Spin in microcentrifuge at 14,000rpm 4˚C for 10-15 min.
4. Aspirate supernatant carefully not to disturb pellet.
5. Add 500 µl 70% ethanol (stored at -20˚C).
6. Spin in microcentrifuge at 14,000rpm 4˚C for 2 min.
7. Aspirate supernatant. Dry pellet at room temperature for 10 min.
8. Resuspend in water or TE buffer. TE buffer is generally preferred,
because the DNA would be more stable.