The Establishment Of The Edible Oil Of Fatty Acid Profiles Library And Its Application In Waste Oil Testing

The different composition and content of fatty acids in vegetable oil were not identical, which caused the difference of the nutritional value of vegetable oils, market prices. In order to get high profits, some criminals use the poor quality of cooking oil, low oil added to the high price, and quality oil, this not only greatly harm the interests of consumers but also threatens the health of consumers. In this paper, we studied six kinds of vegetable oil(tea seed oil, soybean oil, peanut oil, sunflower oil, corn oil and sesame oil) and five kinds of animal oil(chanterelle, butter, duck fat, suet and lard). The fatty acid composition and contents were measured by the potassium hydroxide-methanol solution of methyl pretreatment and gas chromatography-mass spectrometry (GC-MS), respectively. The corresponding dates were analyzed by mathematical statistics software to build vegetable oil and animal oil fatty acid profiles library, respectively, which can qualitatively identify the type of vegetable oil. So we can provide a basis for the detection of waste oil.The main results of this paper are listed as follows:1. Temperature-programmed selection:the conditions remain unchanged such as carrier gas flow rate, initial temperature, the final temperature, split ratio, injection volume, inlet temperature and MS condition. Then, follow in four different pre-programmed temperatures separate the mixed standard solution of fatty acid methyl esters and trans-fatty acid methyl esters. By studying the separation of various fatty acids, we ultimately found that the temperature program for the fourth kind of method is optimal, which was shown as follow: first,130℃ keep 1 min, then 6.5℃/min heated to 170℃,next 2.75℃/min heated to 215℃, keep 12min, last 40℃/min heated to 230℃, holding 3min.2. The split ratio selection:the conditions remain unchanged such as carrier gas flow rate, temperature program, the initial temperature, the final temperature, injection volume, inlet temperature and MS conditions. Then, the pre-treated vegetable oils were measured by the split ratio for 10:1,50:1,75:1,100:1, respectively, then repeated 10 times. By studying samples of fatty acids and the relative standard deviation (RSD) of the situation, we ultimately found that the split ratio of 75:1 is optimal.3. Determination of the fatty acid composition and content of Cooking oil:there are the extract-oils such as tea seed oil, soybean oil, peanut oil, sunflower oil, corn oil, sesame oil, chanterelle, butter, duck fat, suet and lard sample Those oils were pretreated with the potassium hydroxide-methanol solution. Then GC-MS was performed. The 37 kinds of fatty acid methyl esters with mixed standard solution and spectra retrieval (NIST Mass Spectral Database) were used to perform qualitative and quantitative analysis. Each sample was measured three times in parallel, taking the final data as mean±standard deviation, to obtain six kinds of vegetable oil and five kinds of animal oil fatty acid composition and content.4. Statistical analysis:The six kinds of vegetable oil and five kinds of animal oil fatty acid composition and content of the data were analyzed the principal component, cluster and discriminant by SPSS 19.0 software, respectively. Ultimately, we build the vegetable oil and animal oil fatty acid profiles library.5. Atlas library combined with SPSS 19.0 can successfully discriminate and classify 15 kinds of blend,23 kinds of swill oil, and the correct rate reached 100.0%. And also can be used to the analysis of deterioration degree of pure vegetable oil.