Phenol / chloroform extraction .
Dilute your nucleic acid sample to 100–700 µL or divide your samples into tubes such that you have no more than 700 µL per tube .
Add an equal volume of phenol to the tube , vortex vigorously to mix the phases .
Spin in a microfuge at top speed for 1–2 min to separate the phases .
Remove the aqueous phase to a new tube , being careful not to transfer any of the protein at the phase interface .
Repeat the phenol extraction from step 4 .
Repeat the phenol extraction from step 4 .
Extract the sample with an equal volume of chloroform : isoamyl alcohol to remove any trace phenol .
Extract the sample again with an equal volume of chloroform : isoamyl alcohol to remove any trace phenol .
Precipitate the nucleic acid .
