Kannan Prashanth, Konda Ravindranath Ajay Narayan, Domala Sunil Suresh, Oldfield Mitko, Schiffrin Agustin, Gupta Dipti
IITB-Monash Research Academy, IIT Bombay, Mumbai, Maharashtra 400076, India.
Department of Metallurgical Engineering and Materials Science, IIT Bombay, Mumbai, Maharashtra 400076, India.
ACS Appl Mater Interfaces. 2024 Nov 20;16(46):64166-64176. doi: 10.1021/acsami.4c12974. Epub 2024 Nov 5.
The detection of heavy metals in water sources is a critical concern for environmental preservation and public health. However, current electrochemical heavy metal sensors suffer from high sensing limits, cross-sensitivity, and poor selectivity. In this work, we present the possibility of an electrochemical sensor based on a copper (Cu) metal-organic framework for the detection of lead, cadmium, and mercury by replacing Cu metal nodes. The working electrode consists of a ∼5 μm thin layer of copper- tetracarboxyphenylporphyrin (Cu-TCPP) sheets that are adsorbed on a glassy carbon electrode (GCE). Upon interaction with Pb, Cd, and Hg, these ions are adsorbed on and incorporated into the metal nodes of the MOF. The adsorbed metallic species can be oxidized to the ionic form (Pb → Pb) electrochemically, which results in an oxidation response and enables the quantitative detection of these metals. The oxidation peak currents follow a (mostly) bimodal linear regression with a sensing range of up to 30 μM dependent on the deposition time and an ultralow limit of detection (LoD) of up to 5 nM. The system displays robust and selective sensing in saturated solutions of counterions and interfering metal ions (low error margins of <10%). This work represents the first report of a Cu-TCPP-modified GCE anode as an effective electrode for the sensitive detection of multiple heavy metals and an in-depth study into the Cu replacement kinetics of the Cu-MOF.
水源中重金属的检测是环境保护和公众健康的关键问题。然而，目前的电化学重金属传感器存在检测限高、交叉敏感性和选择性差等问题。在这项工作中，我们提出了一种基于铜（Cu）金属有机框架的电化学传感器，通过替换Cu金属节点来检测铅、镉和汞的可能性。工作电极由吸附在玻碳电极（GCE）上的约5μm厚的铜-四羧基苯基卟啉（Cu-TCPP）片层组成。与Pb、Cd和Hg相互作用时，这些离子会吸附并结合到MOF的金属节点中。吸附的金属物种可以通过电化学方式氧化为离子形式（Pb→Pb），这会导致氧化响应并实现对这些金属的定量检测。氧化峰电流遵循（大多）双峰线性回归，检测范围高达30μM，具体取决于沉积时间，最低检测限（LoD）低至5 nM。该系统在抗衡离子和干扰金属离子的饱和溶液中表现出稳健且选择性的传感性能（误差 margins <10%）。这项工作首次报道了Cu-TCPP修饰的GCE阳极作为一种有效电极用于灵敏检测多种重金属，并对Cu-MOF的Cu置换动力学进行了深入研究。
