| In order to establish a fast,efficient and simple multiple pesticide residued method.In this paper,10 pesticides such as carbofuran,fipronil and their metabolites commonly used in the production of fruits and vegetables are used as test objects,leafy vegetables and fruits are used as test samples,and solid phase microextraction(QuEChERS)is used.Method combined with liquid chromatography mass spectrometry/mass spectrometry(LC-MS/MS)method for rapid analysis of pesticide multi-residue samples.The specific research results were listed as follows:(1)LC-MS/MS optimization of 10 kinds of pesticide residues in Chinese cabbage and Apple.The results showed that by selecting the ESI ion source and scanning under the conditions of multiple reaction monitoring scanning(MRM),the ion signals of 10 pesticide targets such as carbofuran and fipronil were stable,with high responsiveness and short detection time;at 2 mmol/L When ammonium acetate+ 0.1% formic acid-acetonitrile is used as the mobile phase,10 pesticides such as carbofuran and fipronil have high response strength and good separation effect.(2)Optimization of pretreatment methods for determination of Carbofuran,fipronil and other 10 pesticide residues in Chinese cabbage and Apple.The extraction solvent,purification method,solid phase extraction packing,eluent and the amount of purifying agent were optimized.The results showed that the recoveries of 10 pesticides,including Carbofuran and fipronil,were between 80% and 120% when acetonitrile was extracted and purified by QuEChERS method,which met the requirements of pesticide residue detection,the recoveries of Carbofuran,fipronil and other 10 pesticides were all higher than 85%,and the mixed detergents of 0.05 g PSA,0.05 g C18 and 0.15 g anhydrous magnesium sulfate(Mg SO4)were selected as detergents,after 2.0 mg/m L GCB was added into the sample solution,the result of pigment removal was nearly colorless,and the recovery rate had little effect.(3)An analytical method for the determination of carbofuran and fipronil,and other 10 pesticide residues in fruits and vegetables by liquid chromatography-tandem mass spectrometry has been established.The results showed that 10 pesticides such as carbofuran and fipronil have good linearity in the range of 0.005-0.40 μg/m L in apples,the correlation coefficient is greater than 0.9967,and the detection limit is0.002mg/kg;Carbofuran and other 10 pesticides in cabbage all have good linearity in the range of 0.002mg/kg,the correlation coefficient is greater than 0.9966,and the detection limit is 0.005-0.40μg/m L carbofuran in apple The recovery rate of 10 kinds of pesticides is 71.9%-110.3%,and the RSD is 2.5%-6.3%.The recovery rate of 10 kinds of pesticides such as carbofuran in Chinese cabbage is 70.4%-106.2%,and the RSD is 2.6%-8.7 %,Compared with National Standard and technical standard,The detection limit and quantitative limit of the method can meet the limit value requirements of pesticide residues in fruits and vegetables.(4)Application of QuEChERS-HPLC-MS/MS in the determination of Carbofuran and other pesticide residues in fruits and vegetables.In this experiment,10 kinds of pesticide residues such as Carbofuran and fipronil in fruits and vegetables were detected by single-needle injection combined with HPLC-MS/MS,this simple and efficient method was extended to the determination of Carbofuran,fipronil and other 10 pesticides in orange,grape,strawberry,Cowpea,celery and spinach.The method is compared with the national standard.The results show that the method can meet the requirements of pesticide residue analysis for many kinds of samples and is suitable for routine analysis of pesticide residue in fruits and vegetables. |
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