The Analysis And Antioxidant Activities Of Essential Oils Based On HPLC-MS And GC-MS

Essential oils contains various volatile substances such as hydrocarbons, alcohols, ketones, aldehydes, esters and oxides, many of which were related with mono-and sesquiterpene structure. It is antimicrobial, insecticidal, antioxidant, and pharmacological, because of which it had been widely used.GC-MS, the main analysis strategy for volatile chemicals, had been widely utilized in the determinations for essential oils. However, structural alterations and cracked fragments of substances with unstable thermal property may occur due to the high temperature. In addition, GC is inappropriate to separate chemicals with high melting and boiling point without derivatization. On the other hand, HPLC is capable of the separation and identification for majority chemicals. Therefore, in order to explore the possibility that LC-MS was used to determine essential oils, it had been analyzed based on LC-MS and GC-MS,.In this research, LC-MS and GC-MS methods were established to determine eight essential oils (snow white, lemon, carnation, green tea, rose, lily, jasmine, lavender). Main contents were listed as follows:1. After optimized by LC-MS, eight essential oils were analyzed and classified into two categories. Ten components, including Ginkgetin, Geranyl formate, Dioctyl maleate, Dimethyl phthalate, Tetradecanoic acid,dodecyl ester, Tetradecanoic acid,2-octyldodecyl ester, Diethyl Phthalate, Fuscoporine, Dioctyl phthalate and Dinonyl phthalate, had been identified.2. Based on optimized GC-MS strategy, eight essential oils were analyzed and classified into four categories according to number of chromatographic peaks and different retention times.64substances had been identified. LC-MS and GC-MS methods were compared in linearity, repeatability, selectivity, sensitivity, time consume and method development, and both were suitable for the determination of essential oils.3. A strategy was established to determine DPPH radical scavening capacity, and it was used to characterize the antioxidant activity of the essential oils. Furthermore, the relationship between antioxidant activity and the change of time was studied. Among eight essential oils, the carnation oil had the maximum scavenging rate reach up to57.9%, and the minimum was lavender oil up to26.1%.