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How to make tris-saturated chloroform - (Oct/30/2012 )

So, I've seen several recommendations when doing phenol:chloroform extraction to first use a saturated phenol:chloroform:isoamyl alcohol solution followed by a second extraction using only chloroform. I have the correct buffered and saturated PCI solution, but now I am at a loss: what exactly constitutes a 'tris-saturated chloroform' and more importantly how do I make it? I have now some pure chloroform (well, alcohol added as a stabilizer...) but what do I need to do to it in order to use it in my extraction? The specific product I have is this: spectrophotometric grade ACS reagent chloroform, Sigma 366919 (C-5312)


Actually I never did it but the recommendations from protocols (and many bioforum posts) all have the same content: buy it as ready-made mix as this doing it yourself is a bothersome and not that easy process. And the finished stuff is cheaper too.


Chloroform has no acid/base groups, and is largely insoluble in water. You can use chloroform without further treatment or pH control, unlike phenol-chloroform or phenol.


I have never heared that until now.
Maybe you mean saturating phenol with Tris (pH 7.9 for DNA and pH 5 for RNA)