Uncovering adulteration and quality variations in commercial lavender essential oils from the Egyptian market using GC–MS and chemometrics

Abstract

Lavender (Lavandula L. spp., Lamiaceae) essential oil is widely valued for its therapeutic effects and aromatic properties. Owing to the growing global demand for this essential oil, the implementation of standardized quality assessment protocol is essential to ensure its quality. This study aimed to perform a comparative metabolite profiling of four commercially available lavender oils in the Egyptian market using Gas chromatography-mass spectrometry (GC-MS) analysis combined with chemometric analysis. A total of 54 volatile metabolites were identified belonging to 8 chemical classes including alcohols, aldehyde/ketone, esters, fatty acids/esters, oxides, aliphatic, monoterpene, and sesquiterpene hydrocarbons. Alcohols and esters represented the abundant classes accounting for 24.7-42.6% and 11.4-46.1%, respectively, of the total volatile composition. Linalool and linalyl acetate, the principal quality markers of lavender oil were comparatively higher in L-Sha (33.61, and 24.72%) and L-Rag (46.09, and 32.65%), indicating their higher quality among the examined samples. In contrast, certain samples exhibited unusually high levels of non-characteristic fatty acid esters and synthetic glycols, suggesting possible dilution or adulteration with carrier oils or formulation additives. Multivariate analysis further demonstrated clear compositional discrimination among samples, confirming substantial variability in the quality of commercial lavender oils available in the Egyptian market. These findings highlight the importance of GC-MS profiling combined with chemometric analysis as a robust tool for authenticity verification, quality control, and detection of potential adulteration in commercial essential oil products.