Gas Chromatography-Mass Spectrometry Analysis of Photosensitive Characteristics in Citrus and Herb Essential Oils

Abstract

Essential oils (EOs) are commonly used in aromatherapy and offer a number of health benefits. However, the photosensitivity of citrus EO family limits their applications. It is important to characterize the compositional changes of EOs upon possible factors affecting their stability, such as light and water content. In this study, we used GC equipped with MS detector to investigate the constituents of commercial citrus EOs (lemon, orange) and herb EOs (clary sage, lavender). The result indicated that limonen was the most abundant compound in citrus EOs and followed by B-pinene or B-myrcene. Linalyl acetate and B-linalool were the major constituents in herb EOs. It is surprised to find that almost no change in chemical compostiion under sunlight exposure for 2hrs. In contrast, the amount of terpene hydrocarbons decreased greatly in citrus OEs with H2O addition and under sunlight exposure, which might be converted to oxidative compounds, such as carveol, p-cymene and limonene oxide. However, herb EOs was much less photosensitive, which are more potential to become a stable material for daily used products application.