Synthesis of Nanostructured Mixed-Valence Fe(II,III) Metal-Organic Framework and Its Application in Electrochemical Sensing of Amoxicillin

The study reports the development of a nanostructured mixed-valence Fe(II)Fe(III)BTC metal-organic framework (BTC = 1, 3, 5-benzenetricarboxylate) modified carbon paste electrode as a novel sensor for the amoxicillin detection in aqueous solutions using square wave voltammetry. The physicochemical properties of FeBTC were characterized using X-ray diffraction spectroscopy, Fourier-transform infrared spectroscopy, Brunauer–Emmett–Teller analysis, electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy. These techniques revealed that FeBTC has a surface area of 1211 m 2 g −1 , a total pore volume of 1.46 cm 3 g −1 , particle sizes ranging from 10 to 20 nm, and a mixed-valence structure. Furthermore, SEM, TEM, and energy-dispersive X-ray spectroscopy exhibited the homogeneous distribution of FeBTC throughout the modified electrode. The electrochemical study showed that the mixed-valence FeBTC improved the electron transfer capabilities of the electrode. Under optimal conditions, the modified electrode exhibited a significant increase in peak height compared to the unmodified electrode (4.6 times higher), with an acceptable reproducibility of 4.88% relative standard deviation. The linear range of the sensor was 1–100 μ M with a good coefficient of determination of 0.9985, and a detection limit of 0.107 μ M. Additionally, the sensor demonstrated excellent performance with the satisfactory recoveries and a good correlation with LC-MS/MS analysis.