Determination of 17 Neonicotinoid Pesticides and Their Metabolites in Baby Fruit and Vegetable Rice Flour by High Performance Liquid Chromatography£­Tandem Mass Spectrometry

KeyWord:baby rice flour  high performance liquid chromatography£­tandem mass spectrometry£¨HPLC£­MS/MS£©  neonicotinoid pesticides  metabolites

Abstract:

      A high performance liquid chromatography£­tandem mass spectrometry£¨HPLC£­MS/MS£© was developed for the simultaneous determination of 17 neonicotinoid pesticides and their metabolites in baby fruit and vegetable rice flour£®After moistened with water£¬the samples were added anhydrous magnesium sulfate£¨MgSO4£©£¬then extracted with acetonitrile solution containing 1%£¨volume fraction£© formic acid£¬followed by QuEChERS purification£®The final extracts were dried under nitrogen£¬and the residues were dissolved in water£­acetonitrile containing 0.1% formic acid£¨4¡Ã1£¬volume ratio£©£¬then separated on an Acquity BEH C18£¨2.1 mm ¡Á 100 mm£¬1.7 ¦Ìm£© column by gradient elution with water containing 0.1% formic acid and acetonitrile as mobile phases£®The analytes were finally detected by HPLC£­MS/MS in positive electrospray ionization£¨ESI+£© mode under multiple reaction monitoring£¨MRM£© mode£¬and quantified by the external standard calibration curve method£®Under the optimal conditions£¬17 analytes were well separated within 10 min£®The calibration curves for 17 analytes were linear in the respective mass concentration ranges with their correlation coefficients£¨r£© larger than 0.995 4£®The limits of detection£¨LODs£© and limits of quantitation£¨LOQs£© were in the range of 0.02£­0.15 ¦Ìg/kg and 0.06£­0.50 ¦Ìg/kg£¬respectively£®The average recoveries for 17 analytes in baby fruit rice flour samples at three spiked levels of LOQ level£¬2.0 ¦Ìg/kg and 10.0 ¦Ìg/kg ranged from 62.5% to 103%£¬with relative standard deviations£¨RSDs£© of 3.5%£­17%£¬while the average recoveries for vegetable rice flour samples at three spiked levels ranged from 66.4% to 108%£¬with RSDs of 4.3%£­13%£®The established method was applied to the detection of 17 neonicotinoid pesticides and their metabolites in baby fruit and vegetable rice flour samples by random sampling principle£¬and acetamiprid was detected in one of the vegetable rice flour samples with content of 7.4 ¦Ìg/kg£®The method was sensitive£¬accurate£¬convenient and reliable£¬and it could meet the requirements for simultaneous detection of 17 neonicotinoid pesticides and their metabolites in baby fruit and vegetable rice flour.