液相色谱串联质谱法测定果园土壤中的多种农药及其代谢产物

Determination of Multiple Pesticides and Their Metabolites in Orchard Soil by Liquid Chromatography-Tandem Mass Spectrometry(LC-MS/MS)

采用液相色谱－串联质谱法（LC‐MS／MS），建立了果园土壤中乐果、甲基托布津、联苯菊酯及其主要代谢产物氧乐果、多菌灵、三氟氯氰菊酯的同时测定方法．样品经二氯甲烷－甲醇（1／1，V／V ）振荡提取后，用LC‐Al‐N固相萃取小柱净化，C18柱分离，以乙腈－乙酸铵溶液（含0.2％甲酸）为流动相梯度洗脱．在多反应监测（M RM ）模式下，获得上述6种化合物的线性范围为2～500μg／kg，检测限分别为0.5，0.2，0.2，0.5，1和1μg／kg，在加标水平为5，10，20μg／kg的平均回收率为72.02％～110.56％，相对标准偏差为2.66％～7.99％，并成功应用于实际土壤中多种农药及其代谢产物的测定．

A simultaneous determination method for the residues of dimethoate ,thiophanate methyl and bifenthrin and their major metabolites ,omethoate ,carbendazim and cyhalothrin ,in orchard soil was de‐veloped by using liquid chromatography‐tandem mass spectrometry （LC‐MS/MS） .Soil samples were ex‐tracted by mechanical shaking with dichloromethane‐methanol （1/1 ,V/V ） ,purified by LC‐Al‐N solid phase extraction （SPE） column ,separated by C18 column ,and eluted by acetonitrile‐ammonium acetate （0.2% formic acid ） as the mobile phases with gradient elution .Under the mode of multiple reaction moni‐toring （MRM） ,the linear ranges of the above 6 compounds were 2~500 μg/kg ,and the limits of detec‐tion were 0.5 ,0.2 ,0.2 ,0.5 ,1 and 1 μg/kg ,respectively .The average recoveries spiked with 5 ,10 and 20 μg/kg ranged from 72.02% to 110.56% with relative standard deviations （RSDs） around 2.66% ~7.99% .This method has been successfully applied to determine multiple pesticides and their metabolites in actual soil samples .