Screen-printed electrodes modified with MOF(Cu-TPA) and activated charcoal for the simultaneous electrochemical detection of emerging pollutants

The present study reports the development and application of a disposable electrochemical platform based on screen-printed carbon electrodes modified with a copper-terephthalate metal–organic framework (MOF(Cu-TPA)) and activated charcoal (CA) for the simultaneous quantification of sulfadiazine (SDZ) and carbaryl (CAR) in environmental matrices. The physicochemical synergy between MOF(Cu-TPA) and CA enhanced the electrode interface by providing higher conductivity, increased surface area, and improved charge-transfer properties. The analysis of the redox behavior of both analytes (SDZ and CAR) using square-wave voltammetry (SWV) and phosphate buffer as supporting electrolyte (0.1 mol L⁻1, pH 7.0) revealed two well-resolved anodic responses at 0.65 and 1.1 V. Under optimized SWV conditions, the sensor displayed linear analytical ranges of 9.0 × 10⁻⁷ to 1.2 × 10⁻5 mol L⁻1 for SDZ and 9.5 × 10⁻⁷ to 4.1 × 10⁻5 mol L⁻1 for CAR, with limits of detection (LOD) of 7.1 × 10⁻⁸ mol L⁻1 (SDZ) and 1.9 × 10⁻7 mol L⁻1 (CAR). The modified electrode exhibited excellent repeatability, reproducibility, and selectivity in the presence of common interferents, and showed no interferences, maintaining the stable analytical signal. When applied to river water samples, the sensing device yielded recovery rates between 95 and 109%, values found to be comparable with those of a reference HPLC method. The findings point to the viability and application potential of MOF(Cu-TPA)/CA-modified SPEs as low-cost and robust sensors for on-site monitoring of emerging pollutants.