提出了气相色谱-串联质谱法同时测定土壤中利谷隆、异丙隆、伏草隆、敌草隆、戊菌隆等5种取代脲类除草剂含量的方法。称取10 g研磨、过筛后的土壤样品,加入10 mL水润湿,用20 mL乙腈和一包含4.0 g硫酸镁和1.0 g乙酸钠的QuEChERS萃取剂提取。取10 mL上清液至25 mL QuEChERS净化管(含1 g硫酸镁、500 mg N-丙基乙二胺和500 mg C₁₈吸附剂)中,涡旋,离心。取5 mL上清液,于50℃水浴中氮吹至近干,残渣用1 mL丙酮复溶后,过0.22 μm微孔滤膜,滤液注入气相色谱仪,以Rxi-5Sil MS色谱柱为固定相,在程序升温条件下分离,所得目标物用三重四极杆串联质谱仪在电子轰击离子源以及多反应监测模式下检测,外标法定量。结果显示:利谷隆、异丙隆、伏草隆、敌草隆、戊菌隆在0.02~5.0 mg·L^-1内与其对应的峰面积呈线性关系,检出限(3S/N)为0.008~0.015 mg·kg^-1;对空白土壤样品进行3个浓度水平的加标回收试验,回收率为87.2%~102%,测定值的相对标准偏差(n=6)为1.8%~3.5%;方法用于实际样品分析,在大豆种植土壤、蔬菜种植土壤中分别检出敌草隆和戊菌隆。

A method for the simultaneous determination of 5 substituted urea herbicides including linuron, isoproturon, fluometuron, diuron and pencycuron in soil by gas chromatography-tandem mass spectrometry was proposed. 10 g of the ground and sieved soil sample was soaked with 10 mL of water, and extracted with 20 mL of acetonitrile and one bag of QuEChERS extractant containing 4.0 g of magnesium sulfate and 1.0 g of sodium acetate. 10 mL of the supernatant was transferred to 25 mL QuEChERS purification tube (containing 1 g of magnesium sulfate, 500 mg of N-propylethylenediamine and 500 mg of C₁₈ adsorbent) for vortex and centrifugation. 5 mL of the supernatant was taken and blown to nearly dry with nitrogen in water bath at 50℃, and then the residue was redissolved with 1 mL of acetone. The obtained solution was passed through 0.22 μm microporous membrane. The filtrate was injected into gas chromatograph with Rxi-5sil MS column as stationary phase, and separated under temperature programmed conditions. The targets separated was detected by triple quadrupole tandem mass spectrometer with electron impact ion source and multiple reaction monitoring mode, and quantified by external standard method. It was shown that linear relationships between values of mass concentration and peak area of linuron, isoproturon, fluometuron, diuron and pencycuron were kept in the range of 0.02-5.0 mg·L^-1, with detection limits (3S/N) in the range of 0.008-0.015 mg·kg^-1. Test for recovery was made on blank soil sample, giving results of in the range of 87.2%-102%, and RSDs (n=6) of the determined values were ranged from 1.8% to 3.5%. This method was applied to the analysis of actual samples, diuron and pencycuron were detected in soybean planting soil and vegetable planting soil, respectively.