δ18O compound-specific stable isotope assessment: An advanced analytical strategy for sophisticated adulterations detection in essential oils - Application to spearmint, cinnamon, and bitter almond essential oils authentication

Natural plant extracts are primarily used as raw materials in the cosmetic and perfumery industry. However, adulterations with petrochemical products are occurring in the market, leading to non-100% natural products. Several analytical techniques such as impurity detection or enantioselective ratio assessments have been previously described as good indicators to detect any addition of synthetic products, but these techniques are ineffective with novel type of synthetic pathways such as semisynthesis. In order to improve authentication, development of advanced analytical strategies such as δ 18 O stable isotopic ratios assessment was tested on spearmint, cinnamon and bitter almond essential oils major metabolites (carvone, (E)-cinnamaldehyde, and benzaldehyde). Natural δ 18 O mean values (δ 18 O Carvone = 18.4‰; δ 18 O Cinnamaldehyde = 13.9‰; δ 18 O Benzaldehyde = 16.5‰) were found to be higher than semisynthetic origin for the 3 studied molecules (δ 18 O Carvone = 9.2‰; δ 18 O Cinnamaldehyde = 8.8‰; δ 18 O Benzaldehyde = 10.9‰). These measurements proved to be efficient to discriminate natural and semisynthetic origins of these components and therefore potentially lead to a novel way to authenticate natural products. • Naturalness authentication of spearmint, bitter almond, and cinnamon essential oils. • Improvement of multi-isotopic data knowledge on essential oils. • Assessment of δ 18 O compound specific isotope analysis using GC-P-IRMS. • Novel hemisynthetic adulteration highlighted using δ 18 O approach.