Toward Sustainable Electrochemical Sensing: ZnFe ₂ O ₄ ‐Modified Screen‐Printed Electrodes for Donepezil Determination

Alzheimer's disease (AD) is a debilitating neurological disorder characterized by progressive cognitive decline. Donepezil (DON), a cholinesterase inhibitor, is among the most widely prescribed medications for symptomatic management. In this study, we developed a sensitive and sustainable electrochemical sensing platform based on screen‐printed electrodes (SPEs) modified with zinc ferrite (ZnFe 2 O 4 ) nanoparticles for the quantitative detection of DON. The incorporation of ZnFe 2 O 4 significantly enhanced electron‐transfer kinetics and increased electroactive surface area. Using square wave voltammetry (SWV), the sensor exhibited a broad linear detection range of 0.02–35 µM, with a low limit of detection (LOD = 1.0 nM) and limit of quantification (LOQ = 3.0 nM). The platform demonstrated excellent reproducibility, long‐term stability, and high selectivity in the presence of co‐administered neuropsychiatric drugs. Owing to its low‐temperature synthesis, minimal sample volume requirements, and reusability, the ZnFe 2 O 4 ‐SPE sensor represents a sustainable and cost‐effective approach for routine monitoring of DON in pharmaceutical formulations and biological matrices.