| If at A260/A280 the purity of DNA is out of the 1.8-2.0 range then the DNA should be purified to remove contaminants. - In the fume hood wearing appropriate protection i.e. gloves etc.. Add an equal Volume of Phenol/Chloroform/isopropanol mixture (in fridge) to the DNA. (make sure the tubes used are resistant to phenol before you begin)
- Vortex the sample thoroughly, solution should be milky.
- Centrifuge at 3,000rpm for 10 minutes.
- Transfer the top layer to a clean tube, be careful not to take over the white fluffy layer. If a small amount is carried over then recentrifage at 3,000rpm for 10 minutes and remove the supernatant to a clean tube.
- If there is a lot of white fluffy material at the interphase then repeat procedure on the sample once more.
- Ethanol precipitate the sample.
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