Development of Co and Cu-based metal-organic frameworks for electrochemical sensing of Pb ions and paracetamol.

Abstract

The present study investigates charge-transfer activity in electrochemistry using a metal-organic framework (MOF) to detect pharmaceutical contaminants (organic substances) along with toxic metals (inorganic pollutants). These contaminants constitute a major threat to human health as well as to the environment because of their persistence, adverse effects, and bioaccumulation. The MOFs (Cu MOF, Cu-Co MOF, and Co MOF) were produced via solvothermal synthesis. They were analyzed by a variety of methods, such as X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The range of crystalline size of the synthesized MOFs using the Debye-Scherrer equation was 80-92 nm. The thermal resistance of the MOFs was examined using thermogravimetric analysis (TGA). In this study, a bimetallic Cu-Co MOF-modified electrode was developed and systematically evaluated as an electrochemical sensing material. In comparison with the monometallic Cu MOF and Co MOF, the Cu-Co MOF exhibited enhanced electrochemical performance, which could be attributed to the synergistic effect of the two metal centers. Furthermore, the Cu-Co MOF served as a dual-electrode system for detecting two analytes (paracetamol and Pb), highlighting its potential as a versatile sensing platform for pharmaceutical and environmental monitoring. For paracetamol, the limit of detection (LOD) and limit of quantitation (LOQ), based on the oxidation current, were 1.98 and 6.59 ppm, respectively. Similarly, based on the reduction current, the calculated LOD and LOQ were 0.20 ppm and 0.68 ppm, respectively. For a heavy metal (Pb), the estimated LOD and LOQ were 0.09 and 0.31 ppm, respectively.