H-SNIF-NMR is the official AOAC method for determining the natural vanillin.
The abundance of five monodeuterated isotopomers for vanillin can be measured by H-SNIF-NMR. The vanillin molecule is represented in figure 11, all observable sites for which the site specific deuterium concentrations can be measured are referenced with a number.
As for the wine or the fruit, the interpretation of results in terms of origin is done by comparison of the isotopic parameters of the sample analyzed with those from a group of referenced molecules of known origin. 
It appears that all the origins of vanillin are well discriminated using H-NMR data. Particularly, vanillin ex-bean can well be distinguished from the other sources, as we can see in figure 12 below.
Additionally, this method is the only one to discriminate between natural and biosynthetic sources of vanillin.