a Remaud et al. (1997).
b John and Jamin (2004).
Also, the development of quantitative 13C-NMR is ongoing. Therefore, first characteristic 13C-distributions in vanillin qualities of different origins have already been obtained (Caer et al., 1991; Tenailleau et al., 2004a, 2004b).
Conclusion
The analytical determination of typical vanilla (extract) ingredients by HPLC and the calculation of their ratios can be considered as a precheck for the authenticity assessment for vanilla. IRMS is a powerful tool to prove the authenticity of vanilla products. Especially since the online technique provides a coupling of GC to IRMS, these measurements have become available without cumbersome isolation steps. The multielement assay with datasets of δ13C-, δ2H-, and δ18O-values should allow to detect trials of fraud.
When a sufficient amount of vanillin can be isolated, quantitative 2H- and 13C-NMR measurements are particularly efficient for distinguishing the different origins of vanillin.
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