Analysis And Extraction Of Unsaturated Fatty Acids In Vegetable Oil

Detection and analysis of main components in vegetable oils were get more attention with the improvement of daily life, especially the unsaturated fatty acid is related to people’s healthy life.It is important and significance to establish a quick and effective detection method and the feasible means of separation. In this paper,fatty acids in nine vegetable oils were analyzed. Especially the three major unsaturated acids:oleic acid,linoleic acid,linolenic acid were analyzed and extracted.All kinds of fatty acid methyl esters in vegetable oils of methyl esterification and its isomer were separated through polarity column and temperature programming by GC-MS.The result showed that highest content of oleic acid in tea oil is about84.92%,highest content of linoleic acid in sunflower seed oil is about59.48%,highest content of linolenic acid in tea oil is about59.54%.The main characteristic peaks of linolenic, linoleic, oleic acid, saturated fatty acids and water in vegetable oils were attributed by ’H-NMR spectra. Benzoic acid was selected as an internal standard to determine the content of linolenic, linoleic, oleic acid, saturated fatty acids and water in vegetable oils by NMR without any pretreatment. The recovery is98%-102%and the RSD of linolenic, linoleic,oleic acid, total saturated fatty acids and water are0.11%、0.12%、0.68%、0.70%、2.65% respectively.the content of linolenic,linoleic,oleic acid, total saturated fatty acids and water can be determined directly and accurately with little sample, This new method is simple and available in studying the quality standards of vegetable oils.Mixed fatty acid methyl esters were separated by urea adduct method.The contents of fatty acid methyl esters in the urea clathrate and its filtrate were measured by GC/MS-QP2010gas chromatograph-mass spectrometer with area normalization method respectively.The result showed that fatty acid methyl esters in the urea clathrate are mainly saturated fatty acid methyl esters and methyl oleate, and a small amount of multivalent unsaturated fatty acid methyl esters,but the content of uns-aturated fatty acid methyl esters in the filtrate is raised from83.77%to99.7%. Oleic acid in tea oil、linoleic acid in sunflower seed oil and linolenic acid in tea oil were extracted respectively by AgNO3silicagel column and petroleum ether as eluent.Saturated fatty acids, oleic acid, linoleic and linolenic were cleared off one by one.All kinds of fatty acids were eluted when5%basically. The high purity of three fatty acids by NMR can provides a good method for separation.