Simultaneous Determination of 12 Pesticides in Root,Leaf and Seed of Lotus,Mud and Field Water by Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectrometry

KeyWord:multi pesticide residue analysis  ultrahigh performance liquid chromatography-tandem mass spectrometry£¨UPLC-MS/MS£©  lotus root  lotus seed

Abstract:

      A sensitive and convenient method was established for the analysis of twelve kinds of pesticide in root,leaf,seed meat and seed shell of lotus,mud and field water by ultrahigh performance liquid chromatography-tandem mass spectrometry£¨UPLC-MS/MS£©.The solid samples were extracted with acetonitrile/water,then salted out with sodium chloride and following by a centrifugal separation,finally purified and eluted with a PestiCarb-SPE column.The water samples were simply enriched,cleaned up and eluted with a BondElut C18-SPE column.The eluted fractions were analyzed by UPLC-MS/MS,and quantified by the matrix external standard method.The mass fragmentation pathway and matrix effect of twelve pesticides were also investigated.The calibration curves for the target compounds were linear in the concentration range of 0ª±005£¨0ª±010£©-2ª±500 mg/L,with their correlation coefficients£¨r2£© more than 0ª±97.The average recoveries£¨Aª±Rª±£© for twelve pesticides at high,middle and low spiked levels in lotus leaf,root,seed and seed shell were between 75ª±6% and 116%,with relative standard deviations£¨RSDs£© of 1ª±3%-25ª±1%,while the Aª±R.for other eleven pesticides except prochloraz in mud were 64ª±6%-104% with RSDs of 0ª±9%-9ª±5%;Besides,the Aª±R.for the analytes in field water ranged from 71ª±2% to 101% with RSDs of 0ª±9%-16ª±9%,except that the Aª±R.for clothianidin at low level,prochloraz and indoxacarb at middle and low levels were less than 70%.The limits of quantitation£¨LOQs£© of this method were not more than 0ª±01 mg/kg and 0ª±1 ¦Ìg/L,except clothianidin.After 10% clomazone-metolachlor-prometryne granules were spread into the lotus root fields by dosages of 630 g aª±iª±/ha and 945 g aª±iª±/ha in one time,final residue test was investigated by this method.Results showed that there were no clomazone and metolachlor residues in lotus root,lotus seed and lotus leaf samples,and the residual amounts of prometryne were not more than 0ª±022,0ª±166,0ª±012 and 0ª±181 mg/kg in the lotus root,lotus seed shell,lotus seed meat and lotus leaf samples,respectively.