Environmental pollution has become an alarming issue for the modern world due to the extensive release of untreated chemical waste into freshwater bodies. Untreated chemical waste poses significant negative impacts on aquatic life and human health. The phenolic compounds are widely used in different industries for dyeing, as food preservatives, and for the production of pesticides. 2,4,6-Trichlorophenol (TCP) is among the most hazardous phenolic compounds that cause several serious health effects. Thus, it is important to monitor TCP in the environmental samples frequently. In the current work, it was aimed to develop a highly sensitive zinc oxide-doped (ZnO) reduce graphene oxide (rGO) composite-based electrochemical sensor for TCP monitoring in the real samples. In this regard, graphene oxide (GO) was simultaneously reduced and doped with ZnO using a facile microwave-assisted synthesis strategy. The resulting ZnO/rGO composite was successfully utilized to fabricate ZnO/rGO-modified glassy carbon electrode (ZnO/rGO/GCE) for the selective and trace level determination of TCP. The conductivity and electrocatalytic behaviors of ZnO/rGO/GCE were examined through different modes of electrochemical setup. Under the optimal operating conditions such as a scan rate of 80 mV.s−1, PBS electrolyte (pH 7.0), and the concentration range of 0.01–80 μM, the fabricated electrochemical sensor manifested outstanding responses for monitoring TCP. The limit of detection (LOD) and limit of quantification (LOQ) of the ZnO/rGO/GCE for TCP were found as 0.0067 μM and 0.019 μM, respectively. Moreover, the anti-interference profile and stable nature of ZnO/rGO/GCE made the suggested electrochemical sensor a superb tool for quantifying TCP in a real matrix.

Fabrication of ZnO-doped reduce graphene oxide-based electrochemical sensor for the determination of 2,4,6-trichlorophenol from aqueous environment
    Abstract
    1 Introduction
    2 Experimental section
        2.1 Reagents and solutions
        2.2 Instrumentation
        2.3 Synthesis of GO and ZnOrGO composite
        2.4 Construction of ZnOrGO-modified electrochemical sensor
    3 Results and discussion
        3.1 Characterization of ZnOrGO composite
        3.2 Characterization of electrodes
        3.3 Determination of TCP at ZnOrGOGCE
        3.4 Selection of electrolyte medium and pH study
        3.5 Scan rate study
        3.6 Anti-interference behavior and stability of ZnOrGOGCE
        3.7 Calibration measurements
        3.8 Analytical application
    4 Conclusion
    References

• Muhammad Nawaz(National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan)
• Huma Shaikh(National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan)
• Jamil A. Buledi(National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan)
• Amber R. Solangi(National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan)
• Ceren Karaman(Department of Electricity and Energy, Akdeniz University, Antalya 07070, Turkey, School of Engineering, Lebanese American University, Byblos, Lebanon) Corresponding author
• Nevin Erk(Faculty of Pharmacy, Department of Analytical Chemistry, Ankara University, 06560 Ankara, Turkey)
• Rozhin Darabi(School of Resources and Environment, University of Electronic Science and Technology of China, Xiyuan Ave, Chengdu 611731, People’s Republic of China)
• Maria B. Camarada(Karlsruhe Institute of Technology, Hermann‑Von‑Helmholtz‑Platz 1, 76344 Eggenstein‑Leopoldshafen, Germany)