A novel approach for lavender essential oil authentication and quality assessment.

Currently, the quality of lavender (Lavandula angustifolia Mill.) essential oil (LEO) is defined and regulated based on standards and methods established by regulatory authorities. Unfortunately, these existing standards and methods are not sufficient for LEO quality evaluation due to the complexity of LEO and adulteration encouraged by a burgeoning market. This study provides an efficient and reliable method for LEO quality assessment and adulteration detection. After a comprehensive investigation, involving a large set of LEO samples (n = 72) analyzed by multiple techniques (GC/MS, GC/Q-ToF, NMR, and chemometric analysis), a new approach named Q-Index was proposed. Fourteen marker compounds, along with trans-furano-linalool oxide acetate (an indicator of synthetic compound adulteration in LEO), were identified. These marker compounds played significant roles in discriminating the adulterated samples from the authentic LEOs. Calculation of the Q-Index value using the identified marker compounds permitted the detection of fraudulent samples. As demonstrated, all the authentic LEOs exhibited high Q-Index values (>100), whereas the adulterated or poor-quality samples displayed low Q-Index values (<100). The NMR-based chemometric analysis, which served as an independent and complementary approach to the GC/MS and Q-Index methods, was applied in order to assess the validity of the Q-Index method. Overall, the results obtained from different methods were in good agreement. Moreover, compared to the NMR method, the Q-Index approach possessed greater sensitivity in detecting LEO adulteration associated with the addition of synthetic compounds. Results of this study demonstrated that the Q-Index method could be successfully applied for LEO quality assessment and adulteration detection. This approach may have a significant potential to improve quality control for the LEO industry.