超高效液相色谱-串联质谱法测定茶叶中6种农药残留

Determination of 6 pesticide residues in tea by ultra performance liquid chromatography-tandem mass spectrometry

目的建立超高效液相色谱-串联质谱法测定茶叶中吡虫啉、多菌灵、啶虫脒、水胺硫磷、三唑磷和甲基异柳磷6种农药残留的方法。方法样品经乙腈提取,NH_2固相萃取小柱富集、净化,以二氯甲烷-甲醇（9：1,V：V）为洗脱溶液;样品经浓缩定容后,采用Thermo C_（18）（2.1 mm×50 mm,1.7μm）色谱柱分离,流速为0.3 mL/min,以水-甲醇-乙腈为流动相进行梯度洗脱,采用超高效液相色谱-串联质谱法多反应监测模式进行测定,采用基质标准溶液外标法定量。结果 6种农药在0.005~0.25μg/mL浓度范围内呈良好的线性关系,相关系数为0.9973~0.9998。当添加水平为0.005、0.025、0.25 mg/kg时,6种农药在茶叶中的加标回收率为72.4%~106.6%,相对标准偏差为1.6%~10.0%。方法定量限为0.5~5μg/kg。结论该方法操作简单、快速,可适用于茶叶中吡虫啉、啶虫脒、多菌灵、水胺硫磷、三唑磷和甲基异柳磷6种农药残留的测定。

Objective To develop a method for the determination of 6 kinds of pesticide residues（imidacloprid,carbendazim,acetamiprid,isocarbophos,triazophos and isofenphos-methyl） in tea by ultra performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS）.Methods The samples were extracted with acetonitrile,then concentrated and cleaned up by NH_2 solid phase extraction（SPE） using dichloromethane-methanol（9：1,V/V） as elution solution.Samples were prepared after concentration and constant volume,and separated by Thermo C18（2.1 mm×50 mm,1.7 μm） column using water-methanol-acetonitrile as mobile phase for the gradient elution at the flow rate of 0.3 mL/min.The target compounds were determined by UPLC-MS/MS under multi reaction monitoring（MRM） mode,and then quantitatively analyzed by external standard method using the matrix-matched standard solution.Results Six kinds of pesticides had good linear relationships between peak areas and concentrations in the range of 0.005~0.25 μg/mL,and the correlation coefficients were 0.9973~0.9998.The spiked recoveries of 6 kinds of pesticides in tea were ranged from 72.4%to 106.6%at the spiked levels of 0.005,0.025 and 0.25 mg/kg,with relative standard deviations of 1.6%~10.0%.The limits of quantification were 0.5~5μg/kg.Conclusion This method is rapid and simple,and can be applied for the determination of 6 kinds of pesticide（imidacloprid,carbendazim,acetamipnd,isocarbophos,triazophos and isofenphos-methyl） residues in tea.