董融融 林丽云 李琪 叶剑芝 林玲 马会芳 曾绍东 杨春亮

摘  要：復杂样品前处理极大的影响分析结果的准确度和分析过程的时效性，因此建立高效的分离分析方法提高检测的准确性和效率具有重要意义。本研究通过一步水热法，合成了碳包覆四氧化三铁磁性纳米粒子（Fe3O4@C-Magnetic nanoparticles，Fe3O4@C-MNPs），利用透射电子显微镜（transmission electron microscope，TEM）、扫描电子显微镜（scanning electron microscope，SEM）、X射线衍射（X-ray diffraction，XRD）、X射线光电子能谱（X-ray photoelectron spectroscopy，XPS）、傅立叶变换红外光谱（Fourier transform infrared spectroscopy，FTIR）、振动样品磁强计（vibrating sample magnetometer，VSM）考察材料的形貌、结构以及磁性能，并以Fe3O4@C-MNPs作为磁性吸附剂，构建磁固相萃取-气相色谱法用于黄瓜中丙溴磷的定量检测，优化了影响磁固相萃取过程农药回收率的主要因素，即磁性吸附材料用量、萃取时间和溶液pH。结果表明：合成的Fe3O4@C-MNPs表面有丰富的官能团，粒径分布均匀，分散性好，具有超顺磁性，对有机磷农药（organophosphorus pesticides，OPs）丙溴磷有较好的吸附富集效果;最优条件下，即Fe3O4@C-MNPs磁性吸附剂用量0.06 g、溶液pH 6、吸附平衡时间10 min、洗脱剂为丙酮时，检测丙溴磷农药的线性范围在0.011～1.0 ?g/mL，检出限为0.0011 mg/kg;使用合成的磁性吸附剂材料Fe3O4@C-MNPs用于磁固相萃取-气相色谱法检测黄瓜实际样品中丙溴磷，回收率在95.0%～101.4%，相对标准偏差（relative standard deviation，RSD）为2.9%～8.5%。该方法有机试剂用量少，吸附剂可重复利用，降低检测成本的同时也更环保，检测效率也得到提高，检测结果准确可靠。

关键词：磁性纳米颗粒;前处理技术;气相色谱;有机磷农药;丙溴磷

Abstract： The pretreatment of complex samples greatly affects the accuracy of the analysis results and the timeliness of the analysis process. Therefore， it is of great significance to establish an efficient separation and analysis method to improve the accuracy and efficiency of detection. In this study， Fe3O4@C-MNPs with rich functional groups on the surface， uniform particle size distribution and good dispersion were successfully synthesized by an improved one-step hydrothermal method. The magnetic nanoparticles which have good adsorption properties for organophosphorus pesticides （OPs） are superparamagnetic. Using Fe3O4@C-MNPs as a magnetic adsorbent， a magnetic solid phase extraction-gas chromatography method was constructed for the quantitative determination of profenofos in cucumber. Transmission electron microscopy （TEM）， scanning electron microscopy （SEM）， X-ray diffraction （XRD）， X-ray photoelectron spectroscopy （XPS）， Fourier transform infrared spectroscopy （FTIR） and vibrating sample magnetometer （VSM） were used to observe the morphology， structure and magnetic properties of the materials. The main factors affecting the recovery rate of pesticides in the process of magnetic solid phase extraction （MSPE） were optimized， including the amount of magnetic adsorption materials， extraction time and solution pH. The experimental results showed that Fe3O4@C-MNPs had a good adsorption and enrichment effect. The optimal condition is that the amount of Fe3O4@C-MNPs magnetic adsorbent is 0.06 g， the solution pH is 6， the adsorption equilibrium time is 10 min， and the eluent is acetone. Under the optimal conditions， the linear range of profenofos pesticide detection was 0.011～1.0 ?g/mL， and the detection limit was 0.0011 mg/kg. The synthetic magnetic adsorbent material Fe3O4@C-MNPs was used to detect profenofos in actual cucumber samples by magnetic solid phase extraction-gas chromatography. The recoveries ranged from 95.0% to 101.4%， and the relative standard deviation （RSD） was 2.9%-8.5%. This method uses less organic reagents and the adsorbent can be reused. The method reduces the cost of testing and is more environmentally friendly. The testing efficiency is also improved. In addition， the detection results are accurate and reliable.

Keywords： magnetic nanoparticles; pretreatment technology; gas chromatography; organophosphorus pesticides; profenofos

有机磷农药（organophosphorus pesticides，OPs）因具备良好的预防、控制及根除害虫的能力而广泛应用于农业生产中以提高农作物产量[1]。然而，由于其较长的半衰期，OPs的残留会对农产品、环境和水系统造成严重污染[2]。……