Electrochemical investigation of an antipyretic drug in plant extracts and environmental samples at the O-MWCNT/CuO nanostructure modified glassy carbon electrode

Opened multiwalled carbon nanotubes (O-MWCNT) were prepared by unzipping MWCNTs using Hummers' method and decorated with CuO to form a nanohybrid (O-MWCNT/CuO) through a simple co-precipitation technique, aimed at developing a novel electrochemical sensor. The O-MWCNT/CuO composite was used to modify a glassy carbon electrode (GCE) for the sensitive detection of the antipyretic drug acetaminophen (ACT) in various matrices. O-MWCNT/CuO was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible spectroscopy, cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS), which confirmed the successful formation of the nanocomposite as well as its electrical conductivity and catalytic properties. The sensor demonstrates a wide linear detection range (0.005–1450 μM), with a low detection limit (LOD) of 7.2 nM and excellent sensitivity of 0.019 μA cm⁻² μM⁻¹. Additionally, the sensor demonstrated good stability (maintaining performance over 65 cycles) and selectivity in various co-interfering compounds. Notably, the electrochemical sensor was applied for the detection of ACT in environmental water samples, pharmaceutical formulations, human biological fluids, and fenugreek plant extracts, achieving good recovery rates (97.37–100.20%) with relative standard deviations (RSD) ranging from 1.0% to 3.3%, using the standard addition method. The novelty of this work lies in the development of a highly sensitive, stable, and selective GCE-modified sensor for ACT detection, with promising applications in real-world sample analysis.