The Method Study For The Extraction And Enrichment Of Organic Pollutants In Food And Environment Samples

With the acceleration of human socialization,a large number of pollutants have been discharged into the environment along with the development of industry and agriculture.Pollutants might enter different foodstuffs the human body through various ways and cause some residues,resulting in a variety of environmental and food safety problems and threatening human health.Therefore,the determanition of contaminants in various matrix samples has become the focus of the whole society.However,the low levels of analytes in complex matrix usually cannot be directly detected by analytical instruments,and the sample pretreatment technology is necessary for the separation,purification,extraction and enrichment of target analytes,so as to improve the sensitivity and accuracy of analysis and detection.In order to achieve efficient and rapid analysis,it is of great significance to develop and employ green extraction solvents with high biocompatibility or adsorbent materials with high selectivity to establish simple,time-saving and miniaturized pretreatment technology（liquid-phase microextraction or solid-phase microextraction）for the determination of various pollutants.Based on the above content,the main work of the paper is as follows:（1）A hydrophobic deep eutectic solvent（HDES）was prepared from tetramethylguanidine chloride and thymol with high biocompatibility.The HDES is environmentally friendly and the aromatic structure can increase the multiple interactions between HDES and analytes to improve the extraction efficiency.Then,the prepared HDES was used as extraction solvent to develop an ultrasound assisted-dispersive liquid-liquid microextraction（UA-DLLME）method combined with highperformance liquid chromatography-ultraviolet detection（HPLC-UV）for the enrichment and determination of four non-steroidal anti-inflammatory drugs（NSAIDs）in real water and milk samples.This method had a wide linear range（5-2000μg/L）and good correlation coefficient（R²>0.994）,and the low limits of detection were 0.5-1μg/L.The proposed method was successfully applied to the extraction and determination of trace NSAIDs in water and milk samples with recoveries in the range of 65.88%-110.80%.（2）Several novel ionic HDESs with low viscosity were prepared based on natural compounds（quaternary ammonium salts and salicylate esters）,the viscosity of which is lower than most reported ionic HDESs（>200 m Pa·s）,among which,the viscosity of the HDES composed of tetrabutylammonium chloride and methyl salicylate is only 89.28 m Pa·s.The prepared HDESs with low toxicity and good biocompatibility,and the low viscosity can facilitate the dispersion of HDES into the aqueous solution,and thus improve the extraction efficiency and reduce the time required to reach extraction equilibrium.Based on the HDESs,an UA-DLLME method combined with HPLC-UV was established for the preconcentration and determination of six endocrine-disrupting phenols（EDPs）in water,milk and beverage.The proposed method had good coefficients of determination（R²>0.9976）in the linear range of 0.5-400μg/L,and the limits of quantitation and limits of detection respectively were0.5-2.5μg/L and 0.25-1μg/L,and the recoveries were 81.79%-109.82%.（3）A type of magnetic mesoporous polydopamine materials with supported metal ions(Fe₃O₄@Si O₂@m PDA-Cu²⁺)was developed for selective enrichment of fluoroquinolone antibiotics（FQs）based on metal affinity chromatography.Compared with the magnetic materials（Fe₃O₄@Si O₂@m PDA）withoutmetalionssupported,the Fe₃O₄@Si O₂@m PDA-Cu²⁺materials had higher selective extraction efficiency for FQs,which can be attributed to the high specific surface area of mesoporous material and the metal affinity interaction of Cu²⁺with founctional groups of analytes,further increasing the adsorption capacity to FQs.