Essential oils: a rich and growing market, synonymous of quality and safety for consumers. And equally rich are “shortcuts” to produce at lower costs.
There are two ways for the adulteration of essential oils: use poor raw material and therefore less expensive in place of the original or mix/dilute the original raw material.
Laboratory analyses are therefore the path required to verify chemical composition and purity. What kind of analysis? It depends on the type of adulteration:
- not all frauds are easily detectable
- hundreds of essential oils lack international shared standards even though EFEO, IFRA and ECHA have defined guidelines for characterization for registration, classification, labelling and compilation of safety data sheets under the EU REACH and CLP Regulations.
What are the most commonly used methods? We start from the physico-chemical ones for a first evaluation of materials (and suppliers) to get to the finest: GC and HPLC physico-chemical analysis are the most advanced methods among them. Some adulterations can be detected simply by GC-MS tests with technology such as GC-IRMS and SNIF-NMR.
The essential oil top adulteration technology includes many analytical techniques: HPLC, FAST GC, GCxGC, IRMS, MS, 1H 13C NMR.
The evaluation of the relationship between natural enantiomers has proved to be a valid criterion for differentiating natural compounds from synthetic.
Also marker can be used: many oils contain indeed a characteristic compound that can be considered for their recognition. Typically, in adulterated oils, markers are found at concentrations lower than normal. Here are some markers:
ESSENTIAL OIL MARKER
Anise (Illicium verum) Cis-anethole/Anisyl alcohol
Artemesia vulgaris Vulgarone
Geranium (North African Type) (-)-(4R)-6,9-Guiadiene / 10-epi-gamma-eudesmol
Lavender (Lavandula augustifolia) (-)-lavandulol / (-)-lavandulyl acetate
Lemon / Mandarin Delta-3-carene
Patchouli (Indonesian) Patchulol
Rosewood (Aniba Spp.) Eremophilene
Rose Otto (R. Centifolia) (Z)-9-nonadecene
Peppermint Piperita Menthafuran