[Babcock_Hall]

IIRC I used various ratios of H₂O to D₂O and took the integrals of the peak of interest.  Fortunately for me, the exchange rate between bulk solvent and the peak of interest was not too fast.  But that method is not applicable in all cases.  I should mention that these hydrogen bonds were first found in small molecules, then enzymologists started noticing unusual fractionation factors in enzymes and reconsidering downfield signals in the serine protease enzymes.  I seem to recall that Kresge and Schowen are two people who have done extensive work in the area o fractionation factors.  A review article by Hibbert and Emsley might also be helpful.  I'll rummage through my old papers and see what I can find.  The gist of the experiment is that the heavier isotope generally enriches in the stiffer bond, and the low-barrier hydrogen bonds sit in an atypical well.  I am not much of a physical organic chemist, so that is the best I can do offhand.