For my experiment, I want to investigate the effect of differing pH on the solubilities of a sparingly soluble drug. However, the solubility is too low for me to conduct a reliable study on the solubility (0.003 mg/ml in water). In ethanol, the solubility increases to 10 mg/ml. Can I simply add buffer solutions and acids into ethanol to change its pH as I would do with water? Are there alternatives to adjusting the pH of ethanol?
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1$\begingroup$ Your basic notion seems wrong. pH aside, solubility in ethanol isn't the same as solubility in water. $\endgroup$– MaxWCommented Apr 3, 2019 at 15:14
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Although pH scale is rather strictly used for aqueous solutions, the concept of pH in organic or non-aqueous solutions is not trivial. It is called apparent pH or operational pH when organic solvents are present. There is a practical problem here as well, do you think your buffers will dissolve in ethanol? Once you figure this out, you can read a section in "pH measurements in Nonaqueous Solvents" by Laitinen & Harris, “Chemical Analysis ─ An Advanced Text and Reference". It is a very useful book.
