磁性分子印迹聚合物的制备及对食品中氯霉素残留的检测

将磁性分离技术和表面分子印迹技术相结合,首先通过化学改性的方式在Fe₃O₄磁性纳米粒子表面接枝双键,以氯霉素(chloramphenicol,CAP)为模板分子、甲基丙烯酸(methacrylic acid,MAA)为功能单体、乙二醇二甲基丙烯酸酯(ethylene glycol dimethacrylate,EDGMA)为交联剂、偶氮二异丁腈(azobisisobutyronitrile,AIBN)为引发剂,采用悬浮聚合法合成CAP的磁性分子印迹聚合物微球(magnetic molecularly imprinted polymer,MMIP),以及对应的非印迹微球(magnetic molecularly non-imprinted polymer,MNIP)。在表征试验中,用傅里叶变换红外光谱仪对每一步合成的产物进行红外光谱检测,用扫描电子显微镜对MMIP和MNIP的微观形态进行观察,用振动磁强计测定磁性纳米粒子和MMIP的饱和磁强度。对MMIP和MNIP的吸附性能进行研究,将MMIP作为固相萃取剂应用于实际样品检测,进行方法学考查。试验结果表明,合成的磁性分子印迹聚合物微球直径400~700 nm,分散性较好,在溶剂中可在外加磁场作用下快速分离。MMIP的最大表观吸附容量可达29.18 mg·g^-1,具有良好的选择识别性能。MMIP作为固相萃取剂在对实际样品进行检测时回收率(86.30%~94.21%)、精密度(RSD≤1.53%)、稳定性(RSD≤1.87%)均良好,且具有较低的检测限(3.0 μg·kg^-1)。将MMIP作为固相萃取剂用于食品中残留氯霉素的分离检测具有良好的效果。

Preparation of magnetic molecularly imprinted polymer and detection of chloramphenicol in foods

In the present study, magnetic separation method was combined with surface molecular imprinting. The magnetic molecularly imprinted polymer (MMIP) for chloramphenicol (CAP) was prepared by suspension polymerization method based on modified Fe₃O₄ nanoparticles as support material, CAP as template molecule, methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as corss-linker and azobisisobutyronitrile (AIBN) as initiator. Meanwhile, the magnetic molecularly non-imprinted polymer (MNIP) was prepared accordingly with the absent of CAP. Each step of the products were characterized by Fourier transform infrared spectrometer, microscopic morphology of MMIP and MNIP were observed by scanning electron microscopy, and the saturation magnetic strength of magnetic nanoparticles and MMIP were detected by vibrating sample magnetometer. The adsorption capacity of MMIP and MNIP were studied by binding experiments. Methodology evaluation was performed for detecting chloramphenicol in foods by using MMIP as solid phase extractant. The obtained MMIPs were 400-700 nm in diameter and had good monodispersity. It could be rapidly separated under an applied magnetic field. The MMIP had high maximum apparent adsorption capacity which was up to 29.18 mg·g^-1 and good selectivity. It had high recovery (86.30%-94.21%), high precision (RSD≤1.53%), good stability (RSD≤1.87%) and low detection limit (3.0 μg·kg^-1), when MMIP was used as solid phase extractant. Thus,the MMIP could be used to detect the chloramphenicol residue in food.