Residue Analysis Of Some Pesticides And Herbicides In Foods By CE/UPLC

In recent years,the abuse of pesticides has seriously damaged the food ecosystem,and threatened the health of human.Thus the food safety has become the focus of attention.It is extremely urgent to establish a simple,rapid and accurate method for the determining of pesticide residues in food.In the process of establishing analysis method,it is crucial to extract the target compound from the sample.Selective accelerated solvent extraction(SASE)is an analytical technique that builds upon ASE by incorporating adsorbent into the extraction step,thereby reducing sample-preparation steps and increasing sample throughput.The method is simple,efficient and automated.Chapter one: The capillary electrophoresis,ultra performance liquid chromatography(UPLC)and accelerated solvent extraction are introduced briefly.The analytical research and development status of benzimidazoles,atrazine and its metabolites,and phenylureas were reviewed.Chapter two: A selective accelerated solvent extraction-capillary electrophoresis was developed for the effective separation and simultaneous determination of the benzimidazoles in animal food.A BGE solution of 50 mM Cit-Na2HPO4·12H2O-10% methanol was used for the separation of the benzimidazoles.The limit of detection of thiabendazole,benomyl,fenbendazole,albendazole and mebendazole were 0.12 ?g/m L,0.24 ?g/mL,0.15?g/mL,0.25?g/mL and 0.21 ?g/mL,respectively.Their average intra-and inter-day analytical precisions(relative standard deviation)were less than 2.7% and 3.4%,respectively.The average recoveries with three spiked levels ranged from 85.2% to 108.3%.Chapter three: A rapid method for the determination of atrazine and its metabolites in fruit was established by selective accelerated solvent extraction-ultra high liquid chromatography(SASE-UPLC).SASE used Cleanert PEP as the adsorbent,so as to the extraction and purification of the samples were completed in one step.The effective separation of atrazine and its metabolites used 2 mmol/L ammonium acetate aqueous solution / acetonitrile(75:25,v/v)in gradient elution with a Acquity BEH C18(2.1 mm×50 mm,1.7?m)column and DAD detector.Atrazine(ATR),Hydroxyatrazine(HA),Deethylatrazine(DEA),Deisopropylatrazine(DIA),deethylisoisopropyl isotide(DEDIA)could separate quickly and effectively in 3.6min.Under the optimum conditions,the detection limit(LOD)of the five drugs ranged from 0.3 to 0.9 ?g/kg.The recoveries of the three spiked levels ranged from 85.9 to 108.8% and the RSD was 1.8~ 4.9%.Chapter four: A highly selective molecularly imprinted polymer combined with matrix solid phase dispersion and accelerated solvent extraction(MIP-MSPD-ASE)was developed for the simultaneous separation and detection of five phenylurea herbicides in vegetables.The molecularly imprinted polymer which showed good selectivity and eliminated matrix interference in the extraction of phenylureas was prepared by precipitation polymerization method.Under the optimum conditions,the detection limit(LOD)of Monoloron,Isoproturon,diuron,Linuron and Tebuthiuron were 0.25~0.7 ?g/kg.The recoveries of the three spiked levels ranged from 84.5 to 95.5%.This method has the characteristic of good selectivity,low solvent consumption.It can be used for the analysis of phenylurea herbicides in vegetables.