气相色谱-串联质谱法测定茶叶中二硫代氨基甲酸酯类农药残留

    Determination of dithiocarbamate pesticide residues in tea by gas chromatography-tandem mass spectrometry

    • 摘要: 建立了基于气相色谱-串联质谱(GC-MS/MS)技术测定茶叶中二硫代氨基甲酸酯类(DTCs)农药的分析方法。DTCs农药首先与氯化亚锡-盐酸溶液在顶空瓶中密闭水浴反应,释放出的二硫化碳(CS2)经正庚烷萃取,采用GC-MS/MS在多重反应监测(MRM)模式下检测分析。结果表明:在1~1000 μg/L范围内,CS2线性关系良好(R2 ≥ 0.999),方法检出限为0.002 mg/kg,定量限为0.005 mg/kg。在空白样品中添加0.005、0.05、0.5 mg/kg 3个水平的CS2,回收率为81%~94%,相对标准偏差为3.7%~5.2%,检测重复性良好。将所建方法应用于30批次茶叶中,发现DTCs检出率为10.00%,最高检出量为0.32 mg/kg。所建方法具有灵敏度高、操作简便、选择性强的优势,适用于茶叶中DTCs农药的检测分析。

       

      Abstract: A method based on gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for the determination of dithiocarbamates pesticides (DTCs) in tea. Firstly, DTC pesticides were reacted with stannous chloride-hydrochloric acid solution in a closed headspace bottle in a water bath. The released carbon disulfide CS2 was extracted by n-heptane and was detected and analyzed in multiple reaction monitoring (MRM) mode with GC-MS/MS. The results showed that the linear relationship (R2≥0.999) of CS2 was good in the mass concentration ranges of 1-1000 μg/L. The method detection limit and quantification limit were 0.002 mg/kg and 0.005 mg/kg, respectively. The fortified recoveries were 81%-94% at three CS2 equivalent levels of 0.005, 0.05, and 0.5 mg/kg, with the relative standard deviation of 3.7%-5.2%, and the detection repeatability was good. The established method was applied to 30 batches of tea samples, and it was found that the detection rate of DTCs was 10.0%, and the maximum detection value was 0.32 mg/kg. The method has the advantages of high sensitivity, simple operation and good selectivity, and is suitable for the detection and analysis of dithiocarbamate pesticides in tea.

       

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