Ni_1–<i>x</i>Mn_<i>x</i>Co₂O₄ Nanoparticles as High-PerformanceElectrochemical Sensor Materials for Acetaminophen Monitoring

Ternary metal oxides, known for their superior electrical and optical properties compared to binary or conventional oxides, hold significant promise for catalysis and energy storage applications. This study investigates the electrochemical performance of Ni_1–<i>x</i>Mn_<i>x</i>Co₂O₄ nanoparticles for detecting acetaminophen in aqueous phosphate buffer solution. The cobaltite nanoparticles were obtained through a simple gel-combustion synthesis, and the sensors were characterized using cyclic voltammetry, chronoamperometry, and differential pulse voltammetry. The anodic peak currents associated with acetaminophen oxidation were assessed by varying the scan rate of current–voltage cycles. Among the sensors tested, the one fabricated with Ni_0.5Mn_0.5Co₂O₄ nanoparticles as an active material exhibited the highest sensitivity of 38.2 μA cm^–2 mM^–1 and a detection limit of approximately 2 μM, demonstrating its potential for sensitive and efficient acetaminophen detection. Moreover, the sensors fabricated using these ternary oxide nanostructures demonstrate a rapid chronoamperometric response time of 35.4 s and a decay lifetime of 0.31 s, highlighting the fast detection capabilities of acetaminophen. The electrochemical oxidation mechanism of acetaminophen and the charge transfer characteristics at the electrode–electrolyte interface have been discussed.