GCMS and IRMS acquire the isotopic fingerprint of vanillin

Dr. Balasz Horvarth, Dr. David Psomiadis, Dr. Bernd Bodiselitsch, Imprint Analytics GmbH

Vanillin is the most popular flavor worldwide. It is traditionally produced from vanilla pods (Vanilla planifolia or other species) by maceration. However, natural vanilla production covers only 1% of global demand. 99 % of vanillin flavor is produced synthetically (petro-chemical origin) or biotechnologically (e.g. from ferulic acid, eugenol).

Between natural and synthetic vanillin is a cost factor of 100:1. It's no wonder that vanillin is one of the most imitated additives in food products worldwide. How can consumers be protected from false declaration and fraud?

Natural and synthetic vanillin is chemically identical, but an isotopic signature is left by the raw material and the production process. Consequently, the "isotopic fingerprint" can be used for differentiation.

GCMS and IRMS reveal compound-specific isotope signature

A common elemental analyzer, coupled to a high resolution sector field mass spectrometer (Isotope Ratio Mass Spectrometer, IRMS) can be used for the determination of the isotope signature from pure material with high precision and accuracy. However, the vanillin (target compound) in a vanilla extract from a complex matrix ranges in concentration from 2 - 300 μg mL-1.
The substances should therefore first be separated from each other, after which isotopic ratios of the target compounds as well as of accompanying compounds when needed can be determined (Compound Specific Isotope Analysis, CSIA).

This can be accomplished by coupling of GCMS and IRMS. In a worldwide first for Shimazdu, the Austrian based company Imprint Analytics uses a Shimazdu GCMS (GCMS-QP2010 Ultra) in conjunction with a Shimazdu Detector Switching Device (DSD) for this coupling in an adaption of the GC(/MS)-IRMS hybrid system originally described by Meier-Augenstein et al. (1994; 1995).

The CSIA technique was first used commercially for the determination of the 13C/12C ratio in vanillin (Hoffman und Salb, 1979). However, the determination of only 13C cannot differentiate between synthetic (petrochemical) and biotechnological (e.g. ferulic acid, eugenol) origin of vanillin. Furthermore, the 13C signature can be manipulated by enriched raw material so as to counterfeit a natural product. More differentiation characteristics should be included.

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