Removal of CsCl/EtBr

1. For 1 ml of DNA sample in a corex tube add 9 ml isopropanol that has been saturated with NaCl-saturated with H2O.
2. Cover well with double layer of parafilm, shake by inversion.
3. Spin (3K, 5 min) and recover the aqueous phase with a DPTP to a new corex tube. If the aqueous phase is not colorless, repeat the extraction step 1 and 2.
4. Bring the recovered phase to 3.5 ml with TE, add 0.5 ml 10 M NH4Ac, 10 ml EtOH, mix (look for the DNA strand).
5. Spin (14 K, 20 min).
6. Resuspend with 2.1 ml TE.
7. NH4Ac/EtOH precipitate the DNA. If there is more than 1 ml of the CsCl in the sample, there may be a CsCl pellet after the first spin. The pellet should disappear after transfer the second spin, if not do a third spin (corex).
8. After the final corex spin, rinse the pellet briefly with 70% EtOH, drain, dry briefly.
9. Resuspend the pellet in 210 µl TE and transfer to a MFT with a siliconized Pasteur pipet. Rinse the corex tube with 70 µl 10M NH4Ac and 700 µl EtOH by voltexing vigorously and transfer this to the MFT with the same siliconized Pasteur pipet.
10. Spin the MFT (14K, 15 min), rinse and resuspend in TE.
11. Quantitate the DNA in the extracted DNA sample, if desired NH4Ac/EtOH precipitate and resuspend the DNA in TE at 1 µg/µl.