超高效液相色谱-串联质谱法测定莲藕、莲叶、莲子、田泥与田水中12种农药残留

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

建立了莲藕、莲叶、莲子肉、莲子壳、田泥和田水中12种农药残留的分析方法。固体样品采用乙腈-水混合提取,氯化钠盐析后离心,分取乙腈提取液过Pesti Carb固相萃取柱净化洗脱,水样采用C18固相萃取柱直接富集净化洗脱,洗脱液浓缩定容后经超高效液相色谱-串联质谱(UPLC-MS/MS)基质外标法定量,并对12种农药的质谱裂解、基质效应进行了探讨。12种农药在0. 005(0. 010)~2. 500 mg/L范围内均呈线性关系,相关系数(r^2)大于0. 97;在低、中、高加标浓度下,莲叶、莲藕、莲子肉和莲子壳中12种化合物的平均加标回收率(A. R.)为75. 6%~116%,相对标准偏差(RSD)为1. 3%~25. 1%;田泥中除咪鲜胺之外,其余化合物的A. R.为64. 6%~104%,RSD为0. 9%~9. 5%;田水中除噻虫胺在低浓度、咪鲜胺和茚虫威在中、高加标浓度下的A. R.<70%外,其余化合物的A. R.为71. 2%~101%,RSD为0. 9%~16. 9%。除田水中噻虫胺外,其余方法定量下限均不大于0. 01 mg/kg和0. 1μg/L。采用该法进行了莲藕田撒施10%异草松·异丙甲草胺·扑草净颗粒剂后的最终残留试验,结果表明:以有效成分剂量630 g a. i./ha和945 g a. i./ha施用1次后,异草松和异丙甲草胺在莲藕、莲子和莲叶中均无残留,扑草净在莲藕、莲子壳、莲子肉和莲叶样品中的残留量分别不超过0. 022、0. 166、0. 012、0. 181 mg/kg。

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 C 18-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 0.005(0.010)-2.500 mg/L,with their correlation coefficients(r 2)more than 0.97.The average recoveries(A.R.)for twelve pesticides at high,middle and low spiked levels in lotus leaf,root,seed and seed shell were between 75.6%and 116%,with relative standard deviations(RSDs)of 1.3%-25.1%,while the A.R.for other eleven pesticides except prochloraz in mud were 64.6%-104%with RSDs of 0.9%-9.5%;Besides,the A.R.for the analytes in field water ranged from 71.2%to 101%with RSDs of 0.9%-16.9%,except that the A.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 0.01 mg/kg and 0.1μg/L,except clothianidin.After 10%clomazone-metolachlor-prometryne granules were spread into the lotus root fields by dosages of 630 g a.i./ha and 945 g a.i./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 0.022,0.166,0.012 and 0.181 mg/kg in the lotus root,lotus seed shell,lotus seed meat and lotus leaf samples,respectively.