A Sustainable Fe-MOF@N-Doped Graphite Electrochemical Platform for Sensitive Dothiepin Determination in Human Plasma

Accurate monitoring of antidepressant drugs is essential for ensuring therapeutic efficacy and minimizing adverse effects, creating a demand for sensitive and reliable analytical methodologies. In the present study, a novel electrochemical sensor was developed for the determination of dothiepin hydrochloride (DOTH) using an iron-based metal–organic framework supported on nitrogen-doped graphite (Fe-MOF@N-dG). The composite material was synthesized through a rapid sonication-assisted approach at ambient temperature, avoiding hydrothermal/solvothermal heating and reducing the consumption of hazardous organic solvents. The physicochemical and electrochemical characteristics of the prepared Fe-MOF@N-dG were investigated using scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and electrochemical impedance spectroscopy. Characterization results confirmed the successful formation of the composite and demonstrated a synergistic interaction between the Fe-MOF and nitrogen-doped graphite. The conductive N-dG network facilitated electron transfer, while the Fe-MOF provided abundant electrocatalytic active sites, which enhanced sensing performance. Electrochemical measurements were performed in Britton–Robinson buffer solution at pH 3.0 under optimized conditions. The fabricated sensor exhibited a linear response over the concentration range of 0.6–100 μM, with a detection limit of 0.073 μM, indicating good sensitivity toward DOTH determination. The proposed method was validated with respect to accuracy and precision and successfully applied to the analysis of spiked human plasma samples. The environmental sustainability of the developed methodology was also assessed using the recently introduced Environmental, Performance, and Practicality Index (EPPI), together with other established green analytical evaluation tools. The findings demonstrate that the Fe-MOF@N-dG platform offers a potentially sensitive, reliable, and environmentally sustainable strategy for electrochemical determination of DOTH in human plasma.