Determination Of Aflatoxin And Polycyclic Aromatic Hydrocarbons In Sesame Oil By Magnetic Solid Phase Extraction

Food safety has always been the focus of public attention,in recent years,food safety incidents have been reported frequently,posing a great threat to the national economy and publ ic health.Edible oils,as an important part of people's daily diet,are often polluted by organic pollutants,which seriously endangers people's health.As the last technical barrier to ensure the safety of oils,the detection method of edible oils have very important practical significance for its research.In the detection of trace organic pollutants?such as AFT,PAHs,et.?,pre-treatment is an important part of the whole detection process,which directly affects the accuracy and reliability.In view of the complexity of the oil matrix and the most pre-treatment methods in edible oils have the defects such as large solvent consumption,time-consuming and high costs,which is difficult to meet the requirements of green,economic and rapid detection under the new situation.In this paper,the magnetic solid extraction pre-treatment technology was applied to the rapid separation,purification and enrichment of trace organics in oil matrix,and some new and effective oil detection methods were established as the supplement methods to the current analysis methods for rapid and batch oil deection.The major research contents of this paper are described as follows:?1?Magnetic graphene oxide?mGO?was successfully synthesized by the chemical precipitation method and used as the adsorbent in magnetic phase extraction?MSPE?for selective extraction and enrichment of aflatoxins B₁?AFB₁?in sesame oil.Meanwhile,quantitative analysis was carried out by combining with enzyme-linked immunosorbent assay?ELISA?,and an analysis method aims to rapid determination of AFB1 in sesame oil by MSPE-ELISA method was established.The method has the advantages of less consumption of organic solvent,simple operation,good precision and satisfactory recoveries results,and can effectively reduce the relative standard deviation?RSD?of the current ELISA method.In addition,the whole pre-treatment process of this method does not need centrifugation and other operations,and can be completed within 10 minutes through a simple vortex,which can greatly improve the field batch screening efficiency of oil samples and reduce the dependence on accessory equipment.?2?Magnetic attapulgite?mATP?was successfully prepared by the in-situ preparation method,which was used as the adsorption for MSPE.The selective adsorption of AFB₁ in sesame oil was achieved by the hydrogen bond interaction between the adsorbent and AFB₁,and combined with high performance liquid chromatography-fluorescence?HPLC-FLD?for the detection of AFB1.A rapid quantitative detection method of AFB1 in sesame oil by MSPE-HPLC method was set up.Compared with immunoaffinity column purification?IAC?,our method greatly decreases the whole pre-treatmeat time,low-cost,and can effectively improve the detection efficiency.Under the optimized MSPE conditions,the limit of detection for the target AFB1 was found to be 0.53?g/kg,the intra-and inter-day relative standard deviations?RSD?were 1.46%⁴.48%and 1.28%².61%,respectively,with satisfactory sensitivity and reproducibility.Besides,the results indicated that the proposed method had the high recoveries for light-colored oils while the recoveries for dark-colored oils were generally low,which showed the applicability for the detection of AFB₁ in light-colored edible oils.?3?Magnetic multiwalled carbon nanotubes?mMWCNTs?were fabricated via co-precipitation method and then served as the adsorbents for MSPE.They were successfully used for extraction and enrichment of polycyclic aromatic hydrocarbons?PAHs?in sesame oil through strong?-?interaction between adsorbent and PAHs,and were detected by tandem gas chromatography-mass spectrometry?GC-MS?.A rapid determination method for EU-limited PAH4 in sesame oil by MSPE-GC-MS was established,PAH4 were benzo[a]anthracene?BaA?,chrysene?Chr?,benzo[b]fluoranthene?BbF?,benzo[a]pyrene?BaP?,respectively.We optimized a series of adsorbent and desorption conditions that affected the extraction efficiency.Under the optimized MSPE conditions,the target PAH4 had good linearity in the concentration range of 2¹00?g/kg,the limits of detection for PAH4 were 0.16⁰.64?g/kg,the intra-and inter-day relative standard deviations?RSD?were 1.55%⁵.83%and 2.02%¹4.71%,respectively.Finally,the method was successfully applied to the detection of PAHs in sesame oil and other edible oils.The recoveries in oil sample were ranged from 84.6%to 96.9%,illustrated that this method was suitable for the detection of four PAHs in actual oil samples.