Acid Phenol Preparation - (Jun/26/2009 )

I need to prepare acid phenol (pH 4) for RNA cleanup (after isolation, to remove DNA). We have solid phenol crystals. How do I prepare the phenol so that it is at pH 4. I know how to prepare buffered phenol pH 8 using TE. Any help would be appreciated.

preparation of acid phenol can be found in these protocols (found in protocols online, the parent site of this forum):

acid phenol method...

and/or

yeast rna acid phenol prep