Electrochemical detection of salicylic acid in fruit products with ternary ZnO/CuO/Y₂O₃ nanocomposites embedded PEDOT:PSS by differential pulse voltammetry

In this approach, a novel electrochemical sensor for the determination of salicylic acid (SA) in fruit juices was developed using a nanocomposite (NC) of ZnO/CuO/Y₂O₃ coated on a glassy carbon electrode (GCE). The ternary metal oxide NCs were synthesized via a facile hydrothermal method and thoroughly characterized using techniques such as X-ray photoelectron spectroscopy (XPS), X-Ray diffraction analysis (XRD), UV–Vis spectroscopy (UV–Vis), Fourier Transform Infrared Spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), and Energy-Dispersive X-Ray Spectroscopy (EDS). The NCs were then used to modify a flat-polished GCE surface, with a conducting polymer binder (PEDOT:PSS) used to facilitate the coating. Differential pulse voltammetry (DPV) was employed for the selective electrochemical detection of SA using this NC-modified GCE sensor. The DPV analysis exhibited a linear relationship between the peak current and SA concentration over a wide range of 1.5 ∼ 15.0 μM, indicating a large linear dynamic range. The sensor demonstrated excellent sensitivity, with a value of 5.79 μA μM⁻¹ cm⁻², and a low limit of detection of 0.18 ± 0.09 μM for SA. Additionally, the sensor's performance was evaluated in terms of pH optimization, response time, stability, reproducibility, and repeatability. Importantly, the developed ZnO/CuO/Y₂O₃ NC-modified GCE sensor was successfully applied to the analysis of real fruit juice samples, showcasing its potential for practical applications in food analysis and quality control.