How does ethanol separates salts from proteins [closed]








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Grad student here messing around with famed [TRIzol](https://en.wikipedia.org/wiki/Trizol) isolation protocol and looking to optimize the protein yield at the end. There are more direct ways to get protein from a sample but I like getting RNA, DNA and protein all in one process if possible.


Specifically I am curious to understand the wash steps in the protocol for the protein pellet. At this point the RNA and DNA phases are removed and you have this white pellet of gunk which includes your protein fraction and undesirable stuff. You proceed to perform a series of wash steps with $\pu{0.3 M}$ guanidine hydrochloride in 95% EtOH. I know the guanidine plays a role as a detergent and relaxing the pellet. What I do not fully understand is how EtOH removes salts?


I am interested in switching to urea for the detergent role. The problem is it is not very soluble at high concentrations (~8M ideally) in ethanol. I could get fair amount in 70% ethanol but I am worried what that might do to my washes. Would I be losing protein as the water concentration increases?


Interested what the community could shed light on this issue.


Thanks in advance.


