Separation And Analysis Of Pesticide Residues In Food Based On MMIP-HPLC

With the wide use of pesticides,food contamination is becoming more and more serious,thus the health of human was threatened seriously.In order to ensure food's safety,magnetic molecularly imprinted polymer(MMIP)with carbon nanotube as supporter which combined the magnetic separation technology and surface imprinting technique was prepared to selectively extract and detect pesticide residues in food.The main research content is as follows:(1)MMIP was prepared by the surface imprinting technology using nicosulfuron as template molecule,magnetic carbon nanotube as supportor,3-aminopropyltriethoxysilane as functional monomer and tetraethyl orthosilicate as cross-linker.After the synthesis,a series of performance characterizations were used to respectively test the functional groups,microstructure,magnetic hysteresis loop and magnetism of MMIP.Meanwhile,the adsorption properties of MMIP including the isothermal adsorption,kinetics and selectivity were studied.Finally,the prepared MMIP was applied for the separation and concentration of sulfonylurea herbicide residues from grains(soybean,wheat and corn),and the extract was detected by high performance liquid chromatography.Under the optimum extraction conditions,relative standard deviations of intra-day and inter-day precisions were in the range of 0.7%~2.4% and 5.3%~8.4%,respectively.Compared with other methods,this method was more rapid,convenient,selective and sensitive in detecting the sulfonylurea herbicide residues in grains.(2)MMIP was prepared via atom transfer radical polymerization using magnetic carbon nanotube as supporter which was synthesized by loading magnetic nanoparticles on the surface of carbon nanotube with hydrothermal method,2-bromide butyl acyl bromide as the initiator,ethylene methacrylate as cross-linker,cuprous bromide as catalyst and N,N,N',N'',N''-pentamethyldiethylenetriamine as ligand.The morphology and composition of MMIP were obtained by a series of performance characterizations.The adsorption performances of MMIP were also studied by isothermal adsorption experiment,dynamic adsorption experiment and selectivity experiment.Finally the prepared MMIP as adsorbent was applied for the extraction and separation of avermectin residual from fish,and the eluent was detected by the ultra high performance liquid chromatography tandem mass spectrometry.Under the optimum extraction conditions,linear range of the method was 0.05~10 ?g·kg-1,relative standard deviations of intra-day and inter-day precisions were in the range of 1.7%~2.9% and 3.4%~5.6%.Compared with other methods,this method not only has high selectivity,sensitivity and accuracy,but also has excellent anti-interference ability in the actual sample application.(3)Thermo-responsive magnetic molecularly imprinted polymer(TMMIP)which had the response to environment temperature change was prepared by combining magnetic responsiveness and selectivity of molecularly imprinting with N-isopropyl acrylamide as thermo-sensitive monomer.The prepared TMMIP was applied to separate and analysize propoxur residues from vegetables,and the eluent was detected by high performance liquid chromatography.The linear range of the method was 0.01~10 mg·kg-1.The relative standard deviations of intra-day and inter-day precisions were in the range of 1.5%~2.4% and 2.9%~5.3%,respectively.These results demonstrated that the extraction method had practical value in the detection of propoxur residues in vegetables(pakchoi,lettuce and rape).Compared with other methods,this method was very convenient,and the prepared TMMIP was able to control the uptake and release of template molecule from matrix in response to external temperature.