Structural characteristics and decomposition analyses of four commercial essential oils by thermal approaches and GC/MS

Abstract

Aromatherapy is an alternative medicine vastly used to modify physical or psychological conditions. Aromatherapy uses a combination of plant materials, essential oils, and other aromatic compounds to alleviate stress. Numerous previous studies have investigated the effects of essential oils on the human body, but few studies on their thermal stability have been conducted. This study investigated the thermal risks associated with essential oils by using differential scanning calorimetry (DSC) with heating rates (β) of 2.0, 4.0, 8.0, and 16.0 °C min−1, thermogravimetry (TG) with β = 10.0, 15.0, 20.0, and 25.0 °C min−1, and Fourier transform infrared spectroscopy (FTIR). The oils’ decomposition excursions, mass loss, and functional groups were identified through DSC, TG, and FTIR, respectively, and thermokinetic parameters, such as the heat of decomposition (ΔH d), apparent exothermic onset temperature (T 0), and peak temperature (T p), also could be determined from DSC and TG tests. The results of this study serve as a reference on the decomposition excursion and thermokinetic parameters of essential oils and on their potential thermal hazard.