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    QuEChERS-高效液相色谱-串联质谱法测定柑普茶中22种氨基甲酸酯类农药的残留量

    Determination of Residues of 22 Carbamate Pesticides in Green Citrus Tea by High Performance Liquid Chromatography-Tandem Mass Spectrometry with QuEChERS

    • 摘要: 取粉状均匀柑普茶样品2.00 g置于50 mL塑料具塞离心管中,用约5 mL蒸馏水浸润10 min,加入20.0 mL乙腈和QuEChERS萃取盐包(4 g MgSO4和1 g NaCl)提取1 min,离心5 min。分取8 mL提取液,用QuEChERS净化管1 200 mg MgSO4、400 mg C18、400 mg N-丙基乙二胺(PSA)、200 mg 石墨化碳黑(GCB)净化,取2 mL上清液过0.22 μm针式有机相滤膜,采用高效液相色谱-串联质谱法(HPLC-MS/MS)测定滤液中22种氨基甲酸酯类农药的含量。以Zorbax-Eclipse-Plus C18色谱柱为固定相,以不同体积比的甲醇和含0.1%(体积分数)甲酸的5 mmol·L−1乙酸铵溶液的混合溶液为流动相进行梯度洗脱,采用电喷雾离子(ESI)源在多反应监测(MRM)模式下进行质谱分析,基质匹配法定量。结果表明,22种农药的质量浓度在0.5~20.0 μg·L−1内与对应的峰面积呈线性关系,测定下限(10S/N)为0.001~0.01 mg·kg−1。按照标准加入法进行回收试验,回收率为76.7%~107%,测定值的相对标准偏差(n=6)为0.70%~9.7%。方法用于分析30批次柑普茶样品,共检出克百威、三羟基克百威、仲丁威、残杀威和灭梭威等5种农药,检出率超过90.0%,其中克百威、三羟基克百威、仲丁威的检出量分别为0.01~0.76 mg·kg−1,0.02~0.08 mg·kg−1和0.01~0.03 mg·kg−1,较多农药检出量超出了GB 2763—2021规定的限量值(0.02 mg·kg−1)。

       

      Abstract: The even powder sample of green citrus tea (2.00 g) was taken and placed into a 50 mL-plastic centrifuge tube, and soaked by about 5 mL of the distilled water for 10 min. The analytes were extracted with 20.0 mL of acetonitrile and QuEChERS salt package (4 g of MgSO4 and 1 g of NaCl) for 1 min and then centrifuged for 5 min. An aliquot (8 mL) of the extract was taken and purified by QuEChERS purification tube containing 1 200 mg of MgSO4, 400 mg of C18, 400 mg of N-propylethylenediamine (PSA) and 200 mg of graphitized carbon black (GCB), and 2 mL of the supernatant was passed through 0.22 μm needle type organic phase filter membrane. The 22 carbamate pesticides in the filtrate were determined by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) using Zorbax-Eclipse-Plus C18 column as the stationary phase, and a mixture of methanol and 5 mmol · L−1 ammonium acetate solution containing 0.1%(volume fraction) formic acid at different volume ratios as the mobile phase for gradient elution. The electrospray ion (ESI) source was used for mass spectrometry analysis in the multiple reaction monitoring (MRM) mode, and the matrix matching method was used for quantification. As shown by the results, linear relationships between the values of the corresponding peak area and mass concentration of 22 pesticides were found in the range of 0.5-20.0 μg · L−1, with lower limits of determination (10S/N) in the range of 0.001-0.01 mg · kg−1. Test for recovery was made by the standard addition method, giving results in the range of 76.7%-107%, with RSDs (n=6) of the determined values in the range of 0.70%-9.7%. This method was used for analysis of 30 batches of green citrus tea samples, and a total of 5 pesticides, including carbofuran, trihydroxycarbofuran, fenobucarb, propoxur and methiocarb, was detected, with detection rate more than 90.0%. Among them, the detection amounts of carbofuran, trihydroxycarbofuran, and fenobucarb were 0.01-0.76 mg · kg−1, 0.02-0.08 mg · kg−1, and 0.01-0.03 mg · kg−1, respectively. The detection amounts of most pesticides exceeded the limit value (0.02 mg · kg−1) specified in GB 2763—2021.

       

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