Protein Binding and Effects of Precipitation

[brewer]

I realize that this isn’t really a chromatography question, but…

Can anyone tell me definitively whether or not plasma protein bound small molecules are completely liberated upon precipitation with ACN or MeOH?

[HW Mueller]

Not necessarily. It is good practice to make sure that these are highly soluble in the extraction solvent, still you have to check the extraction efficiency. We have done this very simply via radioactive standards.