基于金属有机骨架的分散固相萃取-高效液相色谱法测定麦冬等样品中6种新烟碱类农药残留

Determination of six neonicotinoid pesticide residues in Ophiopogonis samples by dispersed solid-phase extraction coupled with high-performance liquid chromatography based on metal-organic frameworks

通过热溶剂法合成了金属有机骨架(MOF)材料NH_(2)-MIL-101(Fe),并建立了基于NH_(2)-MIL-101(Fe)的分散固相萃取-高效液相色谱(DSPE-HPLC)法,用于检测麦冬等药食同源样品中6种新烟碱类农药(噻虫嗪、噻虫胺、吡虫啉、氯噻啉、啶虫脒、噻虫啉)残留。与MIL-53(Al)、多壁碳纳米管(MWCNTs)、ZIF-8及MIL-53(Fe)等吸附剂相比,NH_(2)-MIL-101(Fe)的吸附能力更好,回收率更高;与液相色谱-质谱联用(LC-MS)相比,HPLC在达到检测要求的同时能降低检测成本。利用场发射扫描电子显微镜(FESEM)和傅里叶变换红外光谱(FT-IR)表征制备的NH_(2)-MIL-101(Fe),对吸附剂的种类和用量、萃取溶剂体积、萃取时间、洗脱溶剂体积和萃取洗脱方式进行优化。结果表明,NH_(2)-MIL-101(Fe)稳定性高、选择性好、能在水中快速分散。据此构建的方法检测6种新烟碱类农药,在0.01~2.5 mg/L浓度范围内线性关系良好(R^(2)>0.9993),加标样品检出限(LOD)为0.50~1.0μg/L,平均回收率为93.8%~104.2%,相对标准偏差小于6.5%。本文建立的基于MOF的DSPE-HPLC方法可极大减少实际样品中复杂基质的干扰。

Metal-organic framework(MOF)material NH_(2)-MIL-101(Fe)was synthesized by thermal solvent method,and a dispersive solid-phase extraction coupled with high-performance liquid chromatography(DSPEHPLC)method based on NH_(2)-MIL-101(Fe)was established.It was used to detect the residues of six neonicotinoid pesticides(thiamethoxam,clothiandin,imidacloprid,imidaclothiz,acetamiprid,thiacloprid)in medicine and food homologous products of Ophiopogon.NH_(2)-MIL-101(Fe)had better adsorption capacity and higher recoveries than the adsorbents MIL-53(Al),multi-walled carbon nanotubes(MWCNTs),ZIF-8,and MIL-53(Fe).Compared with the liquid chromatography-mass spectrometry(LC-MS)method,HPLC method can not only meet the detection requirements,but also reduce the detection cost.NH_(2)-MIL-101(Fe)was characterized by field emission scanning electron microscopy(FESEM)and Fourier transform infrared(FT-IR)spectroscopy.The conditions such as the amount and type of adsorbent,volume of extraction solvent,extraction time,volume of elution solvent,and extraction elution methods were optimized.The results showed that NH_(2)-MIL-101(Fe)had high stability,good selectivity,and rapid dispersion in water.For the constructed method based on NH_(2)-MIL-101(Fe),the six neonicotinoids had good linear relationships in the range of 0.01-2.5 mg/L(R^(2)>0.9993),the limits of detection(LODs)of the spiked samples were 0.25-0.5μg/kg,the average recoveries were 93.8%-104.2%,and the relative standard deviations were less than 6.5%.The proposed DSPE-HPLC method based on MOFs can greatly reduce the interference of complex matrix in real samples.