| Edible Vegetable oils play an essential role in our diet, which are indispensable parts of nutrients in the activities of human life, including essential fatty acid, fat-soluble vitamins, phytosterols, polyphenol et al. Edible vegetable oil adulteration severely disrupted the edible oil market, and restricted the development of the healthy industry. Adulteration identif ication technology has become a hot and difficult issue in the field of oil quality and safety. There is of great importance to establish a scientif ic and effective method for strengthening government supervision and protecting the health of consumers. Based on the characteristic markers, it is easy to realize the advantages of confirmation, high-sensitively and multivar iate identif ication. Screening the characteristic markers of edible oils is the key to the muti-adulteration identification. Phenolic compounds as the potential markers, this experiment was chosen magnetic carboxyl multi-walled carbon nanotube composites to extract 23 these compounds in the vegetable oils, with the aid of LC-MS/MS for simultaneous qualitative and quantitative analysis. Then, the characterized library of phenolic compounds were established, which applied to identify the muti-adulteration of plant oils. Moreover, this technology also applied in the field of waste oil adulteration analysis. The specific research results are as follows:1. The simultaneous detection of characteristic components in edible oils was established.Phenolic compounds as the potential markers, they are selected as the targets in this experiment. Magnetic carboxyl multi-walled carbon nanotube composites(c-MWCNT-MNPs) was subjected to separate and enrich the analytes. To evaluate the feasibility of c-MWCNT-MNPs for extraction of phenolics from edible oils, the major parameters affecting extraction efficiency including the adsorbent amount, extraction time, elution volume, desorption solvent and desorption time were optimized. What’s more, the instrument analysis LC-MS/MS conditions were also optimized, such as mobile phase, elution process, collis ion energy. A rapid and high-sensitivity c-MWCNT-MNPs-LC-MS/MS method was established. Under the optimal conditions, 23 phenolic compounds showed good linearity over tested concentration ranges with the correlation coefficients from 0.993~0.999. The limits of detection(LODs) and limits of quantitation(LOQs) were in the range of 0.01 μg/kg~13.60 μg/kg and 0.03 μg/kg~43.00 μg/kg, respectively. The average recoveries ranged from 80.0%~125.9%. The intra- and inter- precision were less than 13.2%, with good repeatability and reproducibility. The results showed that this method is simple, accurate and reliable, and is more suitable for the quantitative analysis of phenolic compounds in vegetable oils.2. The technology of muti-adulteration identification of edible vegetable oils was established.With the help of c-MWCNT-MNPs-LC-MS/MS method, the characteristic database of phenolic compounds in edible oils was established. Several characteristic compounds have been selected from the database, for example, isoflavones in soybean oil, sesamin in sesame oil, 2-(4-Hydroxyphenyl) ethanol in olive oil, sinapic acid in rapeseed oil. The confirmed tec hnology of muti-adulteration identification of edible vegetable oils was established, which provide a technical support for the quality and safety of edible oils.3. Screening novel markers of waste oil, high sensitive identification technology of waste oil adulteration was establishedWaste oil adulteration identif ication is hot and difficult problem in the field of quality and safety of edible vegetable oil. By analyzing the sources and circulatie steps of waste oil, markers of heat stability, and the distribution of markers in edible vegetable oils and waste oils, the new markers were discovered, namely, daidzin and genistein. The results showed that the markers can not only identif ication of adulteration soybean oil or waste oil in plant oils, but also dis tinguish between soybean oil and waste oil. Therefore, this has provided the basis for vegetable oils incorporate with waste oil. |
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