Fe3O4纳米粒子修饰多壁碳纳米管的制备及在水和蜂蜜样品中痕量菊酯类农药分析中的应用

通过化学共沉淀法使Fe₃O₄纳米粒子负载于酸化多壁碳纳米管(AMWNTs)表面,得到Fe₃O₄/AMWNTs磁性纳米材料。该材料具有很好的磁响应度和分散性,将其用于富集痕量拟除虫菊酯类农药残留,结果证明该复合材料对菊酯类农药的吸附性能良好。通过对影响萃取性能的几种因素如离子强度、萃取时间和解吸时间依次进行优化,在最优条件下,建立了Fe₃O₄/AMWNTs磁性分散固相萃取-气相色谱测定6种菊酯类农药残留的分析方法。线性范围在0.5~50 μg/L之间,相关系数(R²)大于0.990,检出限为0.07~0.20 μg/L,精密度为3.8%~8.1%。该方法用于河水、鱼塘水和两种市售蜂蜜中菊酯类农药的残留分析,回收率高于78.4%。该方法操作简便、灵敏度高,能够满足环境水样及蜂蜜样品中痕量菊酯农药残留的分析需求。

Preparation of multi-walled carbon nanotubes decorated with Fe3O4 nanoparticles for determination of trace pyrethroid pesticides in water and honey samples

A magnetic carbon nanotube hybrid material was prepared using a chemical co-precipitation method. The Fe₃O₄ nanoparticles were enclosed onto the surface of the acid multi-walled carbon nanotubes (AMWNTs), and they were identified as Fe₃O₄/AMWNTs composites. This hybrid materials displayed typical superparamagnetic behavior, good dispersibility, and good adsorption capacity for pyrethroid pesticides. A magnetic solid-phase microextraction (MSPE) procedure based on Fe₃O₄/AMWNTs composites, combined with gas chromatography, was developed for the quantification of six pyrethroid pesticides in water and honey samples. Several important parameters affecting the extraction efficiency for six pyrethroid pesticides were optimized in sequential order, including ionic strength, extraction time and desorption time. Under the optimized conditions, this method showed wide linearity ranging from 0.5 μg/L to 50 μg/L with correlation coefficients (R²) higher than 0.990. The limits of detection (LODs) ranged from 0.07 μg/L to 0.20 μg/L at a singal-to-noise ratio of 3. The relative standard deviations (RSDs) ranged from 3.8% to 8.1%. Satisfactory recoveries (>78.4%) were obtained for the simultaneous analysis of the six pyrethroid pesticide residues in river water, fishpond water and two honey samples. This method is sensitive and simple. It can meet the actual requirement for the analysis of trace analytes from environmental water and honey samples.