Sustainable Surfactant-Free Synthesis of MnMoO₄/Carbon Nanofiber Composite for Highly Sensitive Detection of Nimesulide in Biological and Pharmaceutical Matrices

In this study, a high-performance electrochemical sensor based on a MnMoO₄/carbon nanofiber (MnMoO₄/CNF) composite was developed for the sensitive and selective detection of nimesulide, a widely used nonsteroidal anti-inflammatory drug. The MnMoO₄nanoparticles were synthesized via a deep eutectic solvent-assisted hydrothermal route and subsequently integrated onto acid-functionalized carbon nanofibers (CNFs) to form a hybrid electrocatalyst with enhanced conductivity and active surface area. Comprehensive physicochemical characterization using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) confirmed the successful formation of highly crystalline MnMoO₄with uniform dispersion on the CNF matrix. Electrochemical investigations revealed that the MnMoO₄/CNF-modified glassy carbon electrode exhibited outstanding redox activity toward nimesulide, achieving a wide linear detection range of 0.00125–3525.25 μM, a low limit of detection of 0.0026 μM, high sensitivity 1.27 μA μM^–1cm², and a high correlation coefficient (R²= 0.982). The sensor demonstrated favorable surface-controlled electrochemical kinetics, excellent stability over extended operation (1600 s), and high selectivity against common interfering substances such as phenols, uric acid, and glucose. Notably, the sensor exhibited remarkable reproducibility (RSD 98.3%) across independently fabricated electrodes. Real sample analyses in spiked blood plasma and pharmaceutical tablet extracts yielded satisfactory recoveries, validating the sensor’s matrix compatibility and analytical robustness. The synergistic integration of electroactive MnMoO₄and conductive CNF enables efficient electron transfer, high electrocatalytic activity, and structural stability, positioning the MnMoO₄/CNF composite as a promising candidate for practical applications in therapeutic drug monitoring and pharmaceutical quality assurance.