Rapid and sensitive electrochemical detection of paracetamol using EuZrO₃-modified carbon paste electrode

The growing prevalence of pharmaceutical contaminants in the environment underscores the urgent need for high-performance, scalable sensing platforms capable of real-time monitoring. In this study, a novel electrochemical sensor based on a europium zirconate (EuZrO₃)-modified carbon paste electrode (EZO-ME1) was synthesized via a robust high-temperature solid-state route under a reducing atmosphere. The rare-earth based perovskite EZO offers unique redox-active sites, enhanced electrical conductivity, and structural stability, enabling superior electrocatalytic behavior. Detailed physicochemical characterization confirmed the formation of a phase-pure orthorhombic perovskite with nanoscale crystallite dimensions (~ 23 nm, estimated from XRD) and favorable polyhedral coordination, which contribute to efficient surface-confined reactions. Electrochemical performance of EZO-ME1 was evaluated for the detection of paracetamol (PA) as a model analyte. The sensor demonstrated outstanding sensitivity, with a detection limit of 0.096 µM and 0.323 µM, a linear response range of 0.1-1.0 µM, and optimal operation at physiological pH (7.0). Furthermore, the electrode exhibited excellent cycling stability over 25 repetitive scans, high reproducibility across independently fabricated sensors, and negligible baseline drift. Real sample analysis using commercial PA tablets yielded recovery rates between 98% and 103%, confirming the sensor's reliability and practical applicability. This work highlights the multifunctional potential of EZO as an advanced sensing material and its seamless integration into carbon paste electrode platforms, offering a scalable, cost-effective, and high-performance solution for pharmaceutical monitoring and environmental diagnostics.