Substitution-functionalized copper phthalocyanine (CuPc)/carbon nitride (g-C3N4) electrocatalysts for the simultaneous detection of 4-nitroaniline and nitrofurantoin

In this study, we developed a straightforward and highly sensitive electrochemical technique for detecting 4-nitroaniline (4-NA) and nitrofurantoin (NFT) in water samples, utilizing electron-withdrawing group (Cl and F) functionalized copper phthalocyanine (CuPc) modified with graphitic carbon nitride (g-C₃N₄). CuPc and g-C₃N₄ exhibit consistent π–π stacking interactions, with electron-withdrawing substituents on CuPc enhancing the electrochemical sensitivity of 4-NA and NFT, while Cu(II) serves as a single-atom catalyst. The electrochemical performances of 4-NA and NFT were evaluated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) at various pH levels, scan rates, and concentrations. Cl-CuPc/g-C₃N₄ has been shown to have enhanced electrocatalytic activity, demonstrating better electrochemical performances with good selectivity, repeatability, and reproducibility. Consequently, we achieved an extensive linear response range of 0.2498–589.3 μM for 4-NA and 0.2498–589.3 μM for NFT, respectively. It achieved a low detection limit of 6 nM for both analytes, demonstrating high sensitivity. The analysis of environmental water samples indicated the presence of trace amounts of 4-NA and NFT. Consequently, Cl-CuPc/g-C₃N₄ was developed, demonstrating enhanced effectiveness in dual detection. Thus, the employed simple and cost-effective catalysts will be useful with further modification in various electrochemical applications.