Abstract This article reports the synthesis of nickel organic framework capped with polyvinylpyrrolidone (Ni-MOF-PVP) and their modification on glassy carbon (GC) electrode for highly sensitive and selective determination of nitrobenzene (NB) by voltammetry. The Ni-MOF-PVP was synthesized by simple in-situ solvothermal method. The transmission electron microscopy (TEM) images show that the as prepared Ni-MOF was spherical in shape with an average particle size of 322 nm. The particle size was decreased from 322 to 80 nm after the addition of 600 mg PVP to Ni-MOF. Then, the synthesized Ni-MOF-PVP was fabricated on GC electrode by drop casting. It shows two pairs of redox waves at 0.24 and 0.48 V, corresponding to NiII/NiIII and NiIII MOF−1/NiIII MOF−2 in acetate buffer solution at pH 4. Further, the Ni-MOF-PVP modified electrode was used for the selective and sensitive determination of NB. It shows a sharp reduction peak for NB with 70 mV less positive potential and 2-fold higher reduction current when compared to bare GC electrode. The amperometric current response of NB increases while increasing its concentration from 0.2 μM to 1 mM with a correlation coefficient of 0.9924 and the limit of detection (LOD) was found to be 97 nM (S/N = 3). Finally, the practical application of the Ni-MOF-PVP modified electrode was demonstrated by determining NB in tap and lake water samples and these results were validated with gas chromatography–mass spectrometry (GC–MS) method.

中文翻译：

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使用聚乙烯吡咯烷酮的尺寸控制合成 Ni-MOF：用于痕量水平测定硝基苯的新型电极材料

摘要 本文报道了聚乙烯吡咯烷酮封端的镍有机骨架 (Ni-MOF-PVP) 的合成及其在玻碳 (GC) 电极上的修饰，用于通过伏安法对硝基苯 (NB) 进行高灵敏度和选择性测定。Ni-MOF-PVP是通过简单的原位溶剂热法合成的。透射电子显微镜 (TEM) 图像显示所制备的 Ni-MOF 呈球形，平均粒径为 322 nm。在 Ni-MOF 中加入 600 mg PVP 后，粒径从 322 nm 减小到 80 nm。然后，通过滴铸在 GC 电极上制备合成的 Ni-MOF-PVP。它显示了两对 0.24 和 0.48 V 的氧化还原波，对应于 pH 4 的醋酸盐缓冲溶液中的 NiIII/NiIII 和 NiIII MOF-1/NiIII MOF-2。此外，Ni-MOF-PVP 修饰电极用于选择性和灵敏地测定 NB。与裸 GC 电极相比，它显示了 NB 的急剧还原峰，其正电位低 70 mV，还原电流高 2 倍。NB 的电流响应增加，同时将其浓度从 0.2 μM 增加到 1 mM，相关系数为 0.9924，检测限 (LOD) 为 97 nM (S/N = 3)。最后，通过测定自来水和湖水样品中的 NB 证明了 Ni-MOF-PVP 修饰电极的实际应用，并用气相色谱 - 质谱（GC-MS）方法验证了这些结果。与裸 GC 电极相比，它显示了 NB 的急剧还原峰，其正电位低 70 mV，还原电流高 2 倍。NB 的电流响应增加，同时将其浓度从 0.2 μM 增加到 1 mM，相关系数为 0.9924，检测限 (LOD) 为 97 nM (S/N = 3)。最后，通过测定自来水和湖水样品中的 NB 证明了 Ni-MOF-PVP 修饰电极的实际应用，并用气相色谱 - 质谱（GC-MS）方法验证了这些结果。与裸 GC 电极相比，它显示了 NB 的急剧还原峰，其正电位低 70 mV，还原电流高 2 倍。NB 的电流响应增加，同时将其浓度从 0.2 μM 增加到 1 mM，相关系数为 0.9924，检测限 (LOD) 为 97 nM (S/N = 3)。最后，通过测定自来水和湖水样品中的 NB 证明了 Ni-MOF-PVP 修饰电极的实际应用，并用气相色谱 - 质谱（GC-MS）方法验证了这些结果。