Flexible graphene oxide−wrapped SnO₂ hollow spheres with high electrochemical sensing performance in simultaneous determination of 4−aminophenol and 4−chlorophenol

Highlights: •An electrochemical sensor is proposed for the simultaneous analysis of 4−AP and 4−CP. •Graphene oxide−wrapped SnO₂ hollow spheres are used for signal enhancement. •The sensor shows high detection sensitivity and selectivity for 4−AP and 4−CP. •The sensor can be successfully applied to detect 4−AP and 4−CP in water samples. -- Abstract: Graphene oxide−wrapped hierarchical hollow structured SnO₂ spheres were fabricated by hydrothermal strategy and applied to the sensitive electrochemical sensing of phenolic compounds. The as−prepared new nanocomposite modified electrode characterized by morphology, X−ray diffraction, Raman spectroscopy, electrochemical impedance, and electroactive surface area suggested its efficiency for the individual and simultaneous sensing of 4−aminophenol (4−AP) and 4−chlorophenol (4−CP), exhibiting as the remarkable increase in peak currents compared with SnO₂ or graphene oxide modified electrodes. After optimization of electrochemical parameters, the detection limits of 2.2 nM for 4−AP and 3.1 nM for 4−CP were obtained using differential pulse voltammetric method. Finally, the application of the modified electrode in real water samples was evaluated, indicating that it could be used as an excellent platform for the detection of phenolic pollutants.