Chemometric Analysis of Lavender Essential Oils Using Targeted and Untargeted GC-MS Acquired Data for the Rapid Identification and Characterization of Oil Quality

David J Beale,Michael S Dunn,Paul D Morrison,Avinash V Karpe

doi:10.3390/molecules22081339

David J Beale, Michael S Dunn + Show 2 more

Open Access

https://doi.org/10.3390/molecules22081339

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Abstract

Standard raw material test methods such as the ISO Standard 11024 are focused on the identification of lavender oil and not the actual class/quality of the oil. However, the quality of the oil has a significant effect on its price at market. As such, there is a need for raw material tests to identify not only the type of oil but its quality. This paper describes two approaches to rapidly identifying and classifying lavender oil. First, the ISO Standard 11024 test method was evaluated in order to determine its suitability to assess lavender oil quality but due to its targeted and simplistic approach, it has the potential to miss classify oil quality. Second, utilizing the data generated by the ISO Standard 11024 test methodology, an untargeted chemometric predicative model was developed in order to rapidly assess and characterize lavender oils (Lavandula angustifolia L.) for geographical/environmental adulteration that impact quality. Of the 170 compounds identified as per the ISO Standard 11024 test method utilizing GC-MS analyses, 15 unique compounds that greatly differentiate between the two classes of lavender were identified. Using these 15 compounds, a predicative multivariate chemometric model was developed that enabled lavender oil samples to be reliably differentiated based on quality. A misclassification analysis was performed and it was found that the predictions were sound (100% matching rate). Such an approach will enable producers, distributers, suppliers and manufactures to rapidly screen lavender essential oil. The authors concede that the validation and implementation of such an approach is more difficult than a conventional chromatographic assay. However, the rapid, reliable and less problematic screening is vastly superior and easily justifies any early implementation validation difficulties and costs.

Highlights

Adulteration of a pure substance occurs when it is intentionally altered by the addition of foreign materials or exposed to an environment that would induce a change [1]
It is important to note that all the oils used for the experiments detailed were derived from L. angustifolia
The variation of oil composition has been reported to be within industry acceptable limits for the identification of lavender essential oil

Summary

Introduction

Adulteration of a pure substance occurs when it is intentionally altered by the addition of foreign materials or exposed to an environment that would induce a change [1]. In the context of the essential oil industry, adulteration can be used as a means to increase product yields, decrease production costs and/or enhance the perceived quality of the final product, with increased profit being the principal incentive [2,3]. Underlying this is the low manufacturing yields in comparison to the costs of high. There is a lack of regulation regarding the classification and labelling of essential oils, which is highlighted by the difficult challenge of identifying adulterated finished products. For the essential oil of lavender, adulteration has been widely observed. The most common form of adulteration is where oil from the English lavender plant (L. angustifolia Miller) is adulterated with the essential oil from the much cheaper sterile hybrid, lavandin (Lavandula × Intermedia) [10]

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