超高效液相色谱-串联质谱法检测水稻及稻田环境中速灭威的残留

Determination of metolcarb residue in rice and paddy field by ultra high performance liquid chromatography tandem mass spectrometry

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)检测稻田土壤、田水、水稻植株、谷壳和糙米样品中速灭威残留的分析方法。样品经乙腈提取及盐析处理后,用乙二胺-N-丙基(PSA)和白炭黑(SiO2.nH2O)净化,UPLC-MS/MS多离子反应监测模式下测定。结果表明,在0.005～1 mg/L范围内,速灭威的仪器响应值与进样质量浓度间呈良好线性关系,相关系数(r)大于0.98。当添加水平为0.01～5 mg/kg(田水样品中为0.005～1 mg/L)时,速灭威在不同样品基质中的平均回收率为76.7%～107.8%,相对标准偏差(RSD)为1.7%～8.5%,最小检出量(LOD)均为2.0×10-13g,最低检测浓度(LOQ)除在田水样品中为0.005 mg/L外,其余均为0.01 mg/kg。当按推荐剂量的1.5倍(有效成分45 g/hm2)分别施药2次和3次后,采用所建方法测得距最后一次施药10、14和21 d采收的糙米样品中速灭威的最终残留量均为未检出(低于0.01 mg/kg)。

An analytical method was established to determine metolcarb in paddy soil, paddy water, rice straw, rice hull and brown rice by ultra high performance liquid chromatography tandem mass spectrometry （UPLC-MS/MS）. Metolcarb residues in rice samples were extracted by acetonitrile and subjected to a salting-out procedure. The samples were further purified by N-propyl-ethylenediamine （PSA） and white carbon black（SiO2 nH20）, then analyzed by UPLC-MS/MS in the mode of multiple reaction monitoring. The linearity was satisfactory in the concentration range of 0.005 - 1 rag/L, with a correlation coefficient r 〉 0.98. When metolcarb was spiked at 0.01 - 5 mg/kg level in soil matrix and at 0. 005 - 1 mg/L level in water matrix, the average recoveries of metolcarb in different matrices varied from 76.7% to 107.8% ,the relative standard deviation （RSD） varied from 1.7% to 8.5% and the method limit of detection （LOD） was 2. 0 ~ 10-13 g. Moreover, the limit of quantification （LOQ） in paddy soil, rice straw, rice hull and brown rice were 0. 01 mg/kg and 0.005 mg/L in paddy water. The developed method was applied for terminal residue study. When metolcarb was applied for two and three times at the recommended dose of 1.5 times （45 g/hm^2, a. i. ）, the finial residues in brown rice was not detected （lower than 0.01 mg/kg）, at the sampling intervals of 10 d, 14 d and 21 d after the last application