Benzaldehyde site-specific deuterium

Benzaldehyde obtained from bitter almond oil and from the retro-aldol reaction of ciimamic aldehyde from cinnamon originate from different biosynthetic pathways. Therefore, benzaldehyde from bitter almond oil can be easily differentiated from benzaldehyde ex-cassia by comparing tlieir site-specific deuterium distributions. 

While the deuterium spectra of benzaldehydes from different sources do not appear (upon visual inspection) to have significant differences from one another, other than some variation in intensity, the deuterium distribution of benzaldehyde does form clusters on a principal component analysis plot. Benzaldehyde products from the same source have similar deuterium distributions and are therefore close to each otlier on the plot (Figure 1). Thus, the origin of benzaldehyde can be differentiated based on site-specific deuterium distribution. Products outside of the clusters of knoivn samples are normally considered as originating from an unknown source or as a mixture of benzaldehyde from different known sources. 

Deuterium site-specific distribution stores infonnation about the history of a benzaldehyde product. Products from the same source should have similar isotope distribution. Therefore, comparing a test sample s deuterium site-specific distribution with that of standard samples can identify the origin of the test sample. The precondition for a successful identification is that tlie... 

SNIF-NMR is a powerful method for the authentication analysis of benzaldehyde products. However, manufacturing processes may cause the deuterium to shift on the carbonyl site. In some cases, the current SNIF NMR method cannot differentiate abnormal distribution of deuterium caused by adulteration or by production processes that lead to false negative or false positive conclusions of a product. Deuterium on the aromatic sites of benzaldehyde is more stable and is not affected by the known manufacturing processes. The aromatic deuterium distribution is very specific and can be used to classify benzaldehyde products from fossil or different botanical origins. The proposed improvement needs to be further developed and validated. 

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