Electrochemical sensing of atenolol using silver-reduced graphene oxide carbon paste nanocomposite electrode

Atenolol, one of the most prescribed β₁-selective adrenergic blockers, has been increasingly detected in aquatic ecosystems due to incomplete elimination in sewage treatment plants, posing an ecotoxicological hazard to the environment. Here, an electrochemical sensor based on silver-decorated reduced graphene oxide composite carbon paste electrode (rGO@Ag-CPE) was designed for the ultrasensitive electroanalytical determination of atenolol in real-world samples. The morphology and chemical composition of rGO@Ag-CPE were investigated by trans­mission electron microscopy and energy-dispersive spectroscopy analyses, while the electro­chemical properties were evaluated by cyclic and square wave voltammetry techniques. The rGO@Ag-CPE demonstrated excellent electrocatalytic performance toward Atenolol oxidation, attributed to the unique properties of reduced graphene oxide and silver nanoparticles, which provide high conductivity and efficient electrocatalysis, thereby helping to prevent unwanted Atenolol degradation. Under optimized electrochemical sensing conditions, the rGO@Ag-CPE sensor exhibited a linear dynamic range of 20-859 μM (R² = 0.9953), a low detection limit of 2.9 μM, and good reproducibility (relative standard deviation < 4.0 %). A validation study on real-world samples showed good atenolol recovery of 88.8-102% in natural waters and 97-99.2 % in pharmaceutical tablets.