I prepared a 50 mM phosphate buffer in H2O and pH'ed it to 7. I lyophilized it and dissolve it in D2O? What is the pD? And what would be the pT (I would like a tritium water solution, ultimately).
Presumably you’d get some number greater than 7. If you measure [D+] with a pH electrode that would change with time as the heavy water becomes contaminated by H+ ion exchange as well as the water within the glass electrode becoming contaminated with deuterium. I would guess 7.435 based on pK value of 14.869 at 25C. The pK for T2O is reported to be 15.21. Check also the added link,
http://garfield.library.upenn.edu/classics1979/A1979HZ34800001.pdf
Perhaps I am wrong but pD should be absolutely the same than pH. I mean that the pHmeter should be give you the same measure in water or after lyophilization and dissolving with D2O. About pT I wonder exactly what pT would be. In other words I would think from my basic chemistry that the chemical properties of hydrogen do not change if you use deuterium.
Presumably you’d get some number greater than 7. If you measure [D+] with a pH electrode that would change with time as the heavy water becomes contaminated by H+ ion exchange as well as the water within the glass electrode becoming contaminated with deuterium. I would guess 7.435 based on pK value of 14.869 at 25C. The pK for T2O is reported to be 15.21. Check also the added link,
http://garfield.library.upenn.edu/classics1979/A1979HZ34800001.pdf
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