Alkalized Ti3C2 MXene-engineered cost-effective pencil graphite electrode to develop high-performance electrochemical sensor for simultaneous detection of Cd2+ and Pb2+

Heavy metals pose a significant threat to ecosystems and human health due to their toxicity and persistence. In this work, we developed a high-performance electrochemical sensor for simultaneous detection of Cd²⁺ and Pb²⁺ using a cost-effective pencil graphite electrode (PGE) modified with alkalized Ti₃C₂ MXene (alk-MXene/PGE). Cyclic voltammetry and electrochemical impedance spectroscopy were utilized to examine the electrochemical characteristics of different PGEs. Studies revealed that the optimal PGE for subsequent application was the one with HB hardness and a diameter of 2 mm. Compared with bare PGE and Ti₃C₂ MXene modified PGE, alk-MXene/PGE exhibited enhanced electrical conductivity and optimized electrochemical performance, enabling sensitive and simultaneous detection of Cd²⁺ and Pb²⁺ in a single run. Linear relationships were achieved for Cd²⁺ in the range of 5.0 × 10⁻⁴ ∼ 7.0 × 10⁻² mg/L and for Pb²⁺ in the range of 2.0 × 10⁻⁴ ∼ 8.0 × 10⁻² mg/L, with detection limits of 8.10 × 10⁻⁶ mg/L and 9.12 × 10⁻⁶ mg/L, respectively. The developed electrochemical sensor was successfully applied to scallop samples, demonstrating its good practicability. This study underscores the potential of alkalized Ti₃C₂ MXene-modified PGEs in electrochemical sensing of Cd²⁺ and Pb²⁺ simultaneously, paving new avenues for food quality monitoring and environmental analysis.