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    QuEChERS-气相色谱-串联质谱法测定3种食用菌中6种甲氧基丙烯酸酯类杀菌剂的残留量

    QuEChERS-GC-MS/MS Detetermination of Residual Amount of 6 Methoxy Acrylate Fungicides in 3 Edible Mushrooms

    • 摘要: 本工作建立了一种QuEChERS-气相色谱-串联质谱法(GC-MS/MS)测定3种食用菌中6种甲氧基丙烯酸酯类杀菌剂(啶氧菌酯、醚菌酯、嘧螨酯、醚菌胺、吡唑醚菌酯、氟嘧菌酯)残留量的分析方法。称取25.0 g粉碎后的食用菌样品,加入体积比为1∶1的环己烷-乙酸乙酯溶液25 mL,再加入QuEChERS萃取包,涡旋后冷冻离心;将上清液转移至PSA净化管中,涡旋后离心;取上清液10 mL在60℃氮吹至近干,加入体积比为1∶1的环己烷-乙酸乙酯溶液1.0 mL,涡旋溶解后过0.22 μm滤膜,滤液引入Rtx-5 MS色谱柱,载气为氦气,在分流进样、程序升温的条件下进行色谱分离,并在电子轰击离子源(EI)和多反应监测(MRM)模式下进行质谱分析,采用外标法定量。6种甲氧基丙烯酸酯类杀菌剂在0.02~2.0 mg·L-1内与其对应的峰面积呈线性关系,检出限(3S/N)为0.001~0.003 mg·kg-1;对香菇、鸡腿菇和金针菇等3种常见食用菌进行3个浓度水平的加标回收试验,测得回收率为83.5%~105%,测定值的相对标准偏差(n=6)为1.7%~5.0%,重复性RSD在5.0%以内。

       

      Abstract: An analytical method for determination of 6 methoxy acrylate fungicides (picoxystrobin, kresoxim-methyl, fluacrypyrim, dimoxystrobin, pyraclostrobin and fluoxastrobin) in the 3 edible mushrooms by QuEChERS-GC-MS/MS was established in the work. 25.0 g of the crushed edible mushrooms samples were taken, and mixed with by 25 mL of cyclohexane-ethyl acetate solution at a volume ratio of 1:1 to extract the 6 fungicides by shaking. The mixture was vortexed and freeze-centrifuged after adding the QuEChERS extraction package. The extracted solution was then transferred to PSA purification tube. After vortexing and centrifuging, 10 mL of the supernatant was taken and evaporated to near-dryness by N2-blowing at 60℃. 1 mL of cyclohexane-ethyl acetate solution at a volume ratio of 1:1 was added to the residue, and the mixture was dissolved by swirling, and filtered through 0.22 μm filter membrane. The filtrate was introduced to Rtx-5 MS chromatographic column and separated under the condition of split-flow sample introduction and programmed temperature elevation with helium gas as carrier, and then analyzed by MS/MS with EI and MRM mode. External standard method was used in quantitative analysis. Linearity relationships between values of mass fraction of the 6 fungicides and its respective peak areas were found in the same range of 0.02-2.0 mg·L-1, with detection limits (3S/N) of 0.001-0.003 mg·kg-1. Test for the spiked recovery were made at 3 concentritions for the 3 edible mushrooms such as shiitake mushrooms, coprinus comatus and enoki mushrooms, giving results of recovery ranged from 83.5% to 105%. Values of RSDs (n=6) found were in the range of 1.7%-5.0%, with RSDs (n=6) of repeatibility less than 5.0%.

       

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