Water contamination caused by heavy metal pollutants from industrial activities remains a pressing environmental concern. This study reports the development of a novel carbon paste electrode (CPE) modified with ethylenediaminetetraacetic acid (EDTA), polyvinyl alcohol (PVA), and multi-walled carbon nanotubes (MWCNTs) using a mechanochemical method for the electrochemical detection of Cu(II) ions. The modified electrode was thoroughly characterized to evaluate its functional groups, morphology, crystallinity, elemental composition, and electrochemical properties. Electrochemical measurements were performed using cyclic voltammetry (CV) and square-wave anodic stripping voltammetry (SWASV) under optimized conditions in 0.1 M NH₄Cl at pH 5. The EDTA/PVA/MWCNT-CPE exhibited a low detection limit (0.0457 μM), a wide linear range (0.1–2.7 μM), and excellent reproducibility (RSD = 0.51%), repeatability (RSD = 0.43%), and stability (95% retention after six days). Selectivity tests demonstrated high recovery for Cu(II) (99.7%) and Hg(II) (99.89%) with minimal interference. This simple, cost-effective sensor offers high sensitivity and selectivity, making it a promising candidate for Cu(II) detection in environmental monitoring applications.

Enhanced selective Cu(II) detection using a high-performance EDTAPVAMWCNT-modified carbon paste electrode
    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials and instruments
        2.2 Preparation of the electrodes
        2.3 Analytical procedures
    3 Results and discussion
        3.1 Characterization of the electrodes
            3.1.1 FTIR analysis
            3.1.2 Surface morphology of the electrodes
            3.1.3 XRD analysis
            3.1.4 XPS analysis
        3.2 Electrochemical measurements
            3.2.1 Cyclic voltammetry methods
            3.2.2 Square-wave anodic voltammetry for copper detection
        3.3 Optimization of the experimental conditions
            3.3.1 Effect of pH
            3.3.2 Effect of scan rate
        3.4 Analytical performance of EDTAPVAMWCNT-CPE
            3.4.1 Calibration curve and detection limit
            3.4.2 Repeatability and reproducibility studies
            3.4.3 Stability and selectivity studies
        3.5 Novelty of the study
    4 Conclusion
    Acknowledgements 
    References

• Yurika Almanda Perangin Angin(Faculty of Mathematics and Natural Sciences, Department of Chemistry, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia)
• Karna Wijaya(Faculty of Mathematics and Natural Sciences, Department of Chemistry, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia) Corresponding author
• Wega Trisunaryanti(Faculty of Mathematics and Natural Sciences, Department of Chemistry, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia)
• Reka Mustika Sari(Research Center for Food Technology and Processing, National Research and Innovation Agency, Gunung Kidul, Yogyakarta 55861, Indonesia)
• Lia Destiarti(Faculty of Mathematics and Natural Sciences, Department of Chemistry, Universitas Tanjungpura, Pontianak 78114, Indonesia)
• Won‑Chun OH(Department of Advanced Materials and Engineering, Hanseo University, Seosan, Korea)
• Sung Su Kim(Department of Civil and Energy System Engineering, Kyonggi University, Suwon, Gyeonggi‑Do 16227, South Korea) Corresponding author
• Soon Woong Chang(Department of Civil and Energy System Engineering, Kyonggi University, Suwon, Gyeonggi‑Do 16227, South Korea)
• Balasubramani Ravindran(Department of Civil and Energy System Engineering, Kyonggi University, Suwon, Gyeonggi‑Do 16227, South Korea, Department of Microbiology, Faculty of Arts Science Commerce and Management, Karpagam Academy of Higher Education, Coimbatore, Tamil Nadu, India)
• Karthikeyan Ravi(Centre for Herbal Pharmacology and Environmental Sustainability, Chettinad Hospital and Research Institute, Chettinad Academy of Research and Education, Tamil Nadu, Kelambakkam 603103, India)