Hi Enes, according to this instruction manual

"Phenol and phenol:chloroform:isoamyl alcohol are subject to oxidation reactions that will result in yellow or pink color, which serves as an indicator that the phenol is NOT useable for DNA extraction. Using colored phenol or colored phenol:chloroform:isoamyl alcohol will result in quality compromised DNA."

http://www.mobio.com/images/custom/file/protocol/12226-25.pdf

Dear Steingrimur Stefansson  ;

I dont use acid-phenol for DNA isolation, it is for RNA isolation because acidic phenol removes DNA. So I need to use it in the RNA isolation but my problem is It has been prepared one years before and Its pH isn't acidic now, I need to change pH beetwen 4.6 to 6  so Can I change phenol's pH with HCl?

Hi Enes, sorry I don't know the answer. I think you should post this question on RNA topics on RG.

https://www.researchgate.net/topic/rna

https://www.researchgate.net/topic/rna_isolation