One-Step Synthesis of Self-Assembled Flower Shape CuNi-MOF-Based Nanocomposite for Non-Enzymatic Electrochemical Sensing of Atrazine in Real Sample

Abstract

Atrazine is a pesticide that belongs to the class of chlorotriazine and has been proven to cause severe damage to the human endocrine system in case of ingestion. With its harmful effect on animals, plants, and the environment, there is a need for the development of sensor platforms that will be effective in detecting atrazine's presence in an aquatic environment. Metal–organic frameworks (MOFs), as a class of very ordered crystalline materials, have been of great interest because of their potential applications in electrochemical sensors based on distinct chemical and physical properties such as extremely high porosity, large surface area, and easily modifiable structural features. Bimetallic systems, in particular, provide MOFs with improved functionalities required for efficient electrochemical sensing. A bimetallic CuNi MOF–based binary nanocomposite with nitrogen-doped 3-dimensional rGO (N-3DrGO) was designed and was used to fabricate a sensor on the indium tin oxide (ITO) electrode. Powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR), Raman spectroscopy, field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS) techniques were employed for the characterization of CuNi-MOF/N-3DrGO. Further, in atrazine sensing, cyclic voltammetry (CV) analysis and square wave voltammetry (SWV) showed a decrease in current due to the blocking of electron transfer between the electrode and electrolyte interface. Later, SWV analysis showed our designed sensor can sense at a very wide range of 0.5 to 150 ppb with a limit of detection (LOD) of 0.18 ppb. This sensor also exhibited superior selectivity in the presence of other interfering ions and pesticides, stability for up to 5 weeks, and reproducibility. Lastly, a real-time sensing approach was performed by taking water, which showed an average recovery of 99.385%.