Abstract Supported by metal-organic frameworks (MOFs), a new molecular imprinted electrochemical sensor (MIES) taking nano-structure Co2+@Fe3O4 as the support point of receptor was developed for highly sensitive detection of GA in this paper. Gold electrode was modified with Co2+@Fe3O4, then Co2+@Fe3O4/Au was soaked and compounded to Fe3O4@ZIF-67/Au. MIPs film was obtained by potentiostatic polymerization with polypyrrole as monomer and GA as template. SEM, EDS, FTIR, XRD, DPV and EIS characterizations indicate the success of the preparation of the modified electrode. By optimization, the Δi response of MIP/Fe3O4@ZIF-67/Au was strengthened from 25.38 μA to 30.84 μA. The MIP/Fe3O4@ZIF-67/Au sensor showed a superior sensitivity with a lower LOD of 0.297pM (S/N = 3) and a wider linear range of 6–600pM for GA detection, which profits from the combination of high surface area of Co2+@Fe3O4 and high porosity of MOFs. Because of the specificity of molecular imprinted polymers (MIPs), our sensor showed advanced selectivity and not affected by similar structure interfering substances. In addition, the stability, reproducibility and real-sample detection were also satisfactory with the recovery rates between 89.5% and 118.4% and the RSD were lower than 5.5%. This sensitive and simple method can be further used to prepare polypyrrole-based MIES suported by MOFs-Co2+@Fe3O4 for highly sensitive detection of other small and weight molecules.

中文翻译：

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MOFs-Co2+@Fe3O4支持的聚吡咯基MIES对没食子酸的高灵敏度检测

摘要 本文以金属有机骨架（MOFs）为支撑，开发了一种以纳米结构Co2+@Fe3O4为受体支撑点的新型分子印迹电化学传感器（MIES），用于高灵敏度检测GA。用Co2+@Fe3O4修饰金电极，然后将Co2+@Fe3O4/Au浸泡复合成Fe3O4@ZIF-67/Au。以聚吡咯为单体，GA为模板，通过恒电位聚合得到MIPs薄膜。SEM、EDS、FTIR、XRD、DPV 和 EIS 表征表明修饰电极的制备成功。通过优化，MIP/Fe3O4@ZIF-67/Au 的 Δi 响应从 25.38 μA 增强到 30.84 μA。MIP/Fe3O4@ZIF-67/Au 传感器显示出优异的灵敏度，具有较低的 LOD 0.297pM (S/N = 3) 和更宽的 6-600pM 线性范围，用于 GA 检测，这得益于 Co2+@Fe3O4 的高表面积和 MOF 的高孔隙率。由于分子印迹聚合物 (MIP) 的特异性，我们的传感器显示出先进的选择性并且不受类似结构干扰物质的影响。此外，稳定性、重现性和实际样品检测也令人满意，回收率在 89.5% 至 118.4% 之间，RSD 低于 5.5%。这种灵敏而简单的方法可进一步用于制备由 MOFs-Co2+@Fe3O4 支持的基于聚吡咯的 MIES，用于对其他小分子和重量分子的高灵敏度检测。此外，稳定性、重现性和实际样品检测也令人满意，回收率在 89.5% 至 118.4% 之间，RSD 低于 5.5%。这种灵敏而简单的方法可进一步用于制备由 MOFs-Co2+@Fe3O4 支持的基于聚吡咯的 MIES，用于对其他小分子和重量分子的高灵敏度检测。此外，稳定性、重现性和实际样品检测也令人满意，回收率在 89.5% 至 118.4% 之间，RSD 低于 5.5%。这种灵敏而简单的方法可进一步用于制备由 MOFs-Co2+@Fe3O4 支持的基于聚吡咯的 MIES，用于对其他小分子和重量分子的高灵敏度检测。