You may try the NMR. Deuterium will not give a signal so whatever you will see comes from your reagents or the solvents you use. If you use different sample to solvent ratios you should be able to quantify the amount of normal hydrogen in your solutions.

Regards,

Pawel

Deuterium isotope effect can be followed by Infrared, where the D/H ratio shouıld be ca. 1.44

Thanks for your invaluable inputs.