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Raman spectroscopy in the detection of adulterated essential oils: The case of nonvolatile adulterants
Author(s) -
Vargas Jentzsch Paul,
Sandoval Pauker Christian,
Zárate Pozo Paola,
Sinche Serra Marco,
Jácome Camacho Gonzalo,
RuedaAyala Victor,
Garrido Patricia,
Ramos Guerrero Luis,
Ciobotă Valerian
Publication year - 2021
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.6089
Subject(s) - adulterant , essential oil , chemistry , patchouli , canola , gas chromatography , flame ionization detector , pogostemon , chromatography , raman spectroscopy , food science , traditional medicine , medicine , physics , optics
Abstract Essential oils are liquid mixtures of volatile compounds extracted from plants. Their quality is usually controlled via gas chromatography (GC), although with limitations when adulterants are nonvolatile substances. The essential oils of lavender ( Lavandula angustifolia Mill.), peppermint ( Mentha piperita L.), patchouli ( Pogostemon cablin Benth), and their adulterated versions were measured by GC coupled to flame ionization detector (GC‐FID) and Raman spectroscopy. Canola oil, a nonvolatile substance, was used as the adulterant. The adulterated essential oils contained 1%, 3%, 5%, 10%, 15%, and 20% (v/v) of canola oil. Chromatograms of the adulterated essential oils containing 20% (v/v) of canola oil showed decrements in peak areas of the essential oil components, compared with peaks of the pure essential oils. The highest decrements were observed for the adulterated essential oil of patchouli. In general, detection of adulterated essential oils by simple visual inspection of the Raman features was difficult, due to slight differences observed in the spectra. Principal Components Analysis (PCA) allowed achieving a good spectral discrimination between pure and adulterated essential oils. These results suggest that Raman spectroscopy can overcome limitations of GC‐based methods, thus becoming an interesting alternative and complementary technique for quality control of essential oils.