Rafea Osama A S, Abdel-Aziz Ali M, Sayed Mostafa A, Abdelhameed Reda M, Badr Ibrahim H A
Chemistry Department, Faculty of Science, Ain-Shams University, Cairo, 11566, Egypt.
Applied Organic Chemistry Department, National Research Centre, Dokki, Giza, Egypt.
Anal Chim Acta. 2025 Feb 8;1338:343600. doi: 10.1016/j.aca.2024.343600. Epub 2024 Dec 29.
Electrochemical methods, particularly those utilizing sensors, offer distinct advantages over classical analytical methods. They are cost-effective, compatible with mass fabrication, suitable for remote sensing, and can be designed as handheld analyzers. In this context, MIL-101(Cr)-(COOH)₂@MWCNTs was utilized for the first time as a modifier for GCE for the sensitive voltammetric detection of Pb(II), Cu(II), and Hg(II). The surface characteristics of the composite were examined using SEM, EDX, XRD, FTIR, and N₂ adsorption/desorption isotherms. The electrochemical behavior of the modified electrode was investigated using differential pulse anodic stripping voltammetry (DPASV).
The DPAS voltammograms of the composite modified electrode are characterized by a remarkable increase in the oxidation peak currents for Pb, Cu, and Hg, indicating that MIL-101(Cr)-(COOH)₂@MWCNTs composite significantly enhances the electrocatalytic response towards the oxidation of the studied heavy metals. The impact of various parameters, such as accumulation potential, accumulation time, amount of MOF, composite thickness, and supporting electrolyte concentration on the developed sensor's response, were investigated. The analytical performances were also investigated using DPASV. The optimized MIL-101(Cr)-(COOH)₂@MWCNTs/GCE-based sensor exhibited a linear range of 0.11-15.4 μM, 0.11-20.1 μM, and 0.06-20.1 μM, and lower limits of detection (LOD) of 0.08 μM, 0.09 μM, and 0.04 μM for Pb(II), Cu(II), and Hg(II), respectively.
This study introduces a novel MIL-101(Cr)-(COOH)₂@MWCNTs composite-modified GCE, offering exceptional sensitivity, selectivity, and repeatability for detecting Pb(II), Cu(II), and Hg(II). With broad analytical ranges, low detection limits, and successful application in real water samples, the work demonstrates significant potential for environmental heavy metal monitoring and pollution control.
电化学方法，尤其是那些使用传感器的方法，相较于传统分析方法具有明显优势。它们成本效益高，与大规模制造兼容，适用于遥感，并且可以设计为手持式分析仪。在此背景下，MIL-101(Cr)-(COOH)₂@MWCNTs首次被用作玻碳电极（GCE）的修饰剂，用于灵敏伏安检测铅（II）、铜（II）和汞（II）。使用扫描电子显微镜（SEM）、能量散射X射线光谱（EDX）、X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和N₂吸附/脱附等温线对该复合材料的表面特性进行了研究。使用差分脉冲阳极溶出伏安法（DPASV）研究了修饰电极的电化学行为。
复合修饰电极的DPAS伏安图的特征是铅、铜和汞的氧化峰电流显著增加，这表明MIL-101(Cr)-(COOH)₂@MWCNTs复合材料显著增强了对所研究重金属氧化的电催化响应。研究了各种参数，如富集电位、富集时间、金属有机框架（MOF）的量、复合材料厚度和支持电解质浓度对所开发传感器响应的影响。还使用DPASV研究了分析性能。优化后的基于MIL-101(Cr)-(COOH)₂@MWCNTs/GCE的传感器对铅（II）、铜（II）和汞（II）的线性范围分别为0.11 - 15.4 μM、0.11 - 20.1 μM和0.06 - 20.1 μM，检测下限（LOD）分别为0.08 μM、0.09 μM和0.04 μM。
本研究介绍了一种新型的MIL-101(Cr)-(COOH)₂@MWCNTs复合修饰GCE，在检测铅（II）、铜（II）和汞（II）方面具有出色的灵敏度、选择性和重复性。该研究具有广泛的分析范围、低检测限，并成功应用于实际水样中，显示出在环境重金属监测和污染控制方面的巨大潜力。
