石墨烯/聚二甲基硅氧烷涂层顶空固相微萃取与气相色谱联用测定环境水和果汁中菊酯农药残留

Determination of Pyrethroid Pesticide Residues in Environmental Water and Juice Samples by Graphene / Polydimethylsilane Fiber Assisted Headspace Solid-phase Microextraction Coupled with Gas Chromatography

建立了石墨烯/聚二甲基硅氧烷涂层顶空固相微萃取与气相色谱在线联用测定环境水和果汁样品中6种菊酯类农药的检测方法。该涂层的萃取性能优于商用聚二甲基硅氧烷（PDMS,Polydimethylsilane）及聚丙烯（PA,Polypropylene）涂层。对影响萃取性能的因素（如萃取温度、离子强度、萃取时间及解吸时间）依次进行了优化。在最优条件下,丙烯菊酯与联苯菊酯的线性范围为0.02-5μg/L,甲氰菊酯、氯氰菊酯、氰戊菊酯的线性范围为0.1-20μg/L,溴氰菊酯的线性范围为0.2-20μg/L,其相关系数均高于0.99,检出限为6.8-58.2 ng/L,定量下限为18.2-154.9 ng/L。同一涂层的相对标准偏差（RSD,n=5）不高于9.2%,3根涂层之间的RSD为6.7%-10.8%。将该方法用于河水、鱼塘水、苹果汁和橙汁中6种菊酯残留的分析,加标回收率分别为81.6%-92.9%,82.3%-96.1%,78.2%-92.8%和79.9%-91.7%。方法简便、灵敏,能够满足环境水样及浓缩果汁样品中痕量农药残留的分析要求。

A graphene / polydimethylsilane（ graphene / PDMS） fiber assisted headspace solid-phase microextraction combined with gas chromatographic method was developed for the determination of six pyrethroid pesticide residues in environmental water and juice samples. This fiber exhibited a higher adsorption affinity toward pyrethroid pesticides than commercial polydimethylsilane（ PDMS） and polypropylene（ PA） fibers. Several parameters affecting the extraction efficiency for six pyrethroid pesticides,including extraction temperature,ionic strength,extraction time and desorption time,were optimized in sequential order using the graghene / PDMS fiber. The analytical evaluation parameters for six pyrethroid pesticides were studied under the optimized conditions. This method showed wide linearities（ 0. 02- 5 μg / L for allethrin and bifenthrin,0. 1- 20 μg / L for fenpropathrin, cypermethrin and fenvalerate,0. 2- 20 μg / L for deltamethrin）,low detection limits（6. 8- 58. 2 ng / L）,low quantitation limits（18. 2- 154. 9 ng / L） and high correlation coefficients（ r^2 〉0. 99）. The relative standard deviations（ RSD） for five replicate extractions were not more than 9. 2% using one fiber,and the repeatability of fiber-to-fiber were in the range of 6. 7%- 10. 8%. The method was applied in the simultaneous analysis of six pyrethroid pesticide residues in environmental water and juice sam-ples. The recoveries for river water,fishpond water,apple juice and orange juice were in the range of 81. 6%- 92. 9%,82. 3%- 96. 1%,78. 2%- 92. 8% and 79. 9%- 91. 7%,respectively. This method was sensitive and simple,and could meet the actual requirement for the analysis of trace analytes in environmental water and concentrated fruit juice samples.