Plasmid Isolation by ethanol precipitation

1. Follow QIAprep Spin Miniprep Kit protocol from steps 1 - 4.
2. Centrifuge for 1h at 4C and 20000 g.
3. Carefully transfer the supernatant to a new Eppendorf. Be careful not to take any solid parts (this is the cell debris).
4. To the sample add 3 volumes of ice-cold 70% ethanol. If needed divide into several samples.
5. Put samples to -20 for 0.5h to 1 h to precipitate DNA.
6. Centrifuge at 4C for 30 mins at 20000 g.
7. Remove the supernatant.
8. Add 300 uL of 90% ice-cold ethanol. Do not pipette up and down.
9. If the pellet is detached centrifuge for 5 to 10 mins at 4C and 20000 g.
10. Remove the ethanol with a pipette.
11. Let the sample stand open to dry for up to 5 mins.
12. Resuspend in 50 - 100 uL water.