[mark-sev]

This is a 2 or even more part question:

1. H30+ obviously can't form in nonaqueous media, so how can one detemine the activity of H+ in such media, if it is polar probably some dissociation does occour or doesn't it?

I read on wikipedia that it is a possiblity spectrophotometrically, that is logically cause protonated and unprotonated species would have different cromophores but how could one correlate that with the activity of H+.

2.In the acidic and alkaline "error" range where the response of glass electrode is unlinear, the pH in aqueous media can be measured spectrophotometrically (read on wikipedia) so again what is the correlation. I also read that it could be done with NMR but replacing the solvent H2O with D2O, i don't have enough knowledge of NMR at the time to explain myself this so could you please.

Thank you very much for the answers and help, i hope that i had written in an understandable way.
 

[Arkcon]

I can only guess, because I don't have that particular wikipedia page, and I likewise don't have the references that page used, but apparently, the spectrophotometric method is using some sort of indicator, and is determining pK(solvent), to determine pH(solvent).

As I'd heard it, if you wanted a "correct"* value for pH, in a non aqueous solvent, say, 10% ethanol in water, what you'd do is fill the pH electrode with 10% ethanol (and the correct ions, usually conc. KCl saturated with AgCl, for a silver electrode), and standardize it with pH buffers, likewise 10% ethanol, with their concentrations calculated for the lower activity of the solvent.  Then you can use it for an unknown sample.

*Disclaimer:  this is of course not the definition of pH, the activity of hydrogen in pure water, but instead of hydrogen activity.

**Super Disclaimer:  I have, often, measured and reported the pH of an HPLC mobile phase, that was not pure aqueous, with a pH meter meant only for aquesous solutions.  I know the answer was technically wrong.  But it was reproducible, and gave expected results, so sometimes people can just "go with the flow," depending on the rigor of their application.