[Arkcon]

Say guys, I was wondering, what happens if you try to take the pH of essentially pure solvent with a pH meter?

Duh, Arkcon:, pH is invalid except in an aqueous solution.

I know that, and I know its less than accurate to take the pH of a buffer that's mixed with solvent, as in an HPLC eluent.  Still, methods are written to do that, and I assume, the results are reproducible enough.

Still, when you have essentially pure alcohol, and a small amount of water that may contain a small amount of alkaline component, say a cleaning agent, can you expect the pH meter to give consistent, if not absolutely accurate, results?

[Borek]

As far as I know - no. That is, I guess as long as you are using the same setup and identical electrode, results can be reproducible, but their meaning is not clear, and they are not guaranteed to be identical if tests are done elsewhere with a different electrode.

Disclaimer: I have never tested it by myself, that's what I remember from discussions about pH measurements that I listened to long ago.