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Phenol Contamination - (Apr/14/2007 )

Hi friends
I am struggling to extract purified DNA however to my distress always come up with phenol contamination (evident from a peak at 270nm in the UV spectra). During the DNA purification i take extra care to flush out phenol by repeated treatment with chloroform. Eagerly waiting for your help...


When doing this, one thing have to bear in mind. You have to take out only the upper phase of the solution after added phenol chloroform. Have to be careful when taking that layer out cause sometimes this is where the phenol usually appear.


phenol is soluble in ethanol (about any alcohol really)

So I make my phenol problems go away by ethanol percipitation of the DNA, followed by a 70% ethanol wash of pellet.


Or you should try double cloroform extraction.


if you don't want to loose any DNA, pellet with isopropanol or butanol


I do washing steps with ethanol and Na-Citrat.


Na citrate?

Why do you use that? (just curious)
My ethanol percipitation uses Na acetate. Is Na citrate better?


Hmmm, I am just following an Invitrogen protocol ... pH should be similar, no? Maybe because it smells better? No, honestly, I don't know what is better, but I think both is working.