Forensic adulteration

It is often difficult to detect the adulteration of products. Classic chemical analysis reaches its limits when the proportions of the ingredients present are illegally increased. Those adulterations with e.g. water, sugars and organic acids are difficult to detect.

This is where stable isotope analysis comes into play.

Stable isotope analysis uses the unique isotope pattern in products, which is determined by various factors such as plant species (C3, C4 and CAM plants), plant tissue water and production processes. This information is retained in various substances such as sugars, proteins and acids, and even flavours (e.g. vanillin). It is also used to verify the feeding of animals (e.g. organic milk, oat-fed goose).

The isotope method can be used to detect adulteration, such as the addition of cane or beet sugar, based on their stable isotope signature. The isotopic profile of carbon and hydrogen differs significantly for such world market sugars in contrast to many other agricultural products. Therefore, the isotope method can detect adulteration in specialty sugars such as coconut sugar, as well as in endogenous sugars in fruit juices, vinegar (e.g. wine vinegar), honey or wine.

A common method

Various standards such as AIJN, AOAC, OENOC and DIN now list the isotope method for detecting adulteration. In addition, Agroisolab uses its own methods, for example to analyse the fermentation basis of wine vinegar.

In the field of flavour analysis, such as vanillin, the stable isotope method is currently certainly the most powerful method. It can provide the distinction of the origin of the vanillin (from the pod, biochemical or fossil) even in highly processed products. With the further developed Vanilla method of Agroisolab, the authenticity can still be verified even in the lower ppm range (2 ppm).

According to the position paper of the German Stable Isotope Working Group, a δ¹³C of -21.5 ‰ is now considered as unlikely for natural vanillin from the pod.

Finally, the stable isotope method is one of the few analytical methods that can be used to detect the watering of products such as wine and fruit juice.

This is only a brief overview of the possibilities of the stable isotope method. For further information do not hesitate to ask us.