Key Laboratory of Chemistry of Northwestern Plant Resources of the CAS and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, PR China; University of Chinese Academy of Sciences, Beijing, 100039, PR China.
Key Laboratory of Chemistry of Northwestern Plant Resources of the CAS and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, PR China.
Anal Chim Acta. 2017 Jan 1;949:23-34. doi: 10.1016/j.aca.2016.11.016. Epub 2016 Nov 11.
A novel magnetic polyethyleneimine modified reduced graphene oxide (FeO@PEI-RGO) had been fabricated based on a self-assemble approach between positive charged magnetic polyethyleneimine (FeO@PEI) and negative charged GO sheets via electrostatic interaction followed by chemical reduction of GO to RGO. The as-prepared FeO@PEI-RGO was characterized by transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), thermal gravimetric analyzer (TGA), vibrating sample magnetometer (VSM) and zeta potential analysis, and then was successfully applied to determine four phenoxy acid herbicides and dicamba in rice coupled with high performance liquid chromatography (HPLC). As a surface modifier of RGO, PEI not only effectually affected the surface property of RGO (e.g. zeta potential), but also changed the polarity of RGO and offered anion exchange groups to polar acidic herbicides, which would directly influence the type of adsorbed analytes. Compared with FeO@PEI, FeO/RGO and FeO@PEI-GO, the as-prepared FeO@PEI-RGO, integrating the superiority of PEI and RGO, showed higher extraction efficiency for polar acidic herbicides. Besides, the adsorption mechanism was investigated as well. It turned out that electrostatic interaction and π-π interaction were considered to be two major driving force for the adsorption process. Response surface methodology (RSM), a multivariate experimental design technique, was used to optimize experimental parameters affecting the extraction efficiency in detail. Under the optimal conditions, a satisfactory performance was obtained. The calibration curves were linear over the concentration ranging from 2 to 300 ng g with correlation coefficients (r) between 0.9985 and 0.9994. The limits of detection (LODs) were in the range of 0.67-2 ng g. The recoveries ranged from 87.41% to 102.52% with relative standard deviations (RSDs) less than 8.94%. Taken together, the proposed method was an efficient pretreatment and enrichment procedure and could be successfully applied for selective extraction and determination of polar acidic herbicides in complex matrices.
一种新型的磁性聚乙烯亚胺修饰还原氧化石墨烯（FeO@PEI-RGO）已通过静电相互作用自组装制备，正电荷的磁性聚乙烯亚胺（FeO@PEI）和带负电荷的 GO 片之间形成，然后通过化学还原 GO 得到 RGO。所制备的 FeO@PEI-RGO 通过透射电子显微镜（TEM）、傅里叶变换红外光谱（FT-IR）、X 射线衍射（XRD）、热重分析仪（TGA）、振动样品磁强计（VSM）和 Zeta 电位分析进行了表征，并成功应用于高效液相色谱（HPLC）结合测定水稻中的四种苯氧羧酸类除草剂和麦草畏。作为 RGO 的表面改性剂，PEI 不仅有效地影响了 RGO 的表面性质（如 Zeta 电位），而且改变了 RGO 的极性，并提供了阴离子交换基团，用于极性酸性除草剂，这将直接影响被吸附分析物的类型。与 FeO@PEI、FeO/RGO 和 FeO@PEI-GO 相比，所制备的 FeO@PEI-RGO 结合了 PEI 和 RGO 的优势，对极性酸性除草剂具有更高的萃取效率。此外，还研究了吸附机制。结果表明，静电相互作用和π-π 相互作用被认为是吸附过程的两个主要驱动力。响应面法（RSM）是一种多元实验设计技术，用于详细优化影响萃取效率的实验参数。在最佳条件下，得到了令人满意的性能。校准曲线在 2 至 300ng g 的浓度范围内呈线性，相关系数（r）在 0.9985 至 0.9994 之间。检出限（LOD）范围为 0.67-2ng g。回收率在 87.41%至 102.52%之间，相对标准偏差（RSD）小于 8.94%。总之，该方法是一种有效的预处理和富集方法，可成功应用于复杂基质中极性酸性除草剂的选择性提取和测定。
