Investigation of the adulteration of essential oils by GC-MS

Background: A lack of regulation about the chemical composition of essential oils and the growing popularity of these oils among consumers presents an urgent need for the accurate characterization of various oil types from a variety of manufacturers. The aim of this paper was to characterize the composition of essential oils bought from a popular retail location, with the goal of understanding the chemical composition and presence of adulterants with potential toxicity. Methods: Reported herein is an investigation into the components of a variety of essential oils using gas chromatography-mass spectrometry (GC-MS). The investigation initially focused on two popular oils, tea tree and lavender oil, and then moved to investigate four additional essential oils from the same brand (sandalwood, rose, eucalyptus, and lemongrass). Results: Results of this analysis indicated that all six store brand essential oils contained Carbitol (in concentrations from 23% to 35%), and four of the six oils had diethyl phthalate (in concentrations ranging from 0.33% to 16%). These toxicants are particularly concerning because they are known inhalation hazards, and the intended usage of these oils is for aromatherapy (i.e. inhalation). Conclusion: These results highlight a potentially significant and under-reported health concern from inhalation of toxic contaminants in the store brand oils, and showcase the need for more regulation and transparency about the composition of these commercial products.