Differential Pulse Voltammetric Determination of Sildenafil Using Nano-Iron Oxides Modified Electrode

Ferromagnetic nanoparticles (FeNPs) have been successfully prepared by using solvothermal reduction method with polyethylene glycol as a solvent. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, nitrogen adsorption/desorption isotherms, and vibrating sample magnetometer. The magnetic properties and morphology of iron oxides was found to depend on the solvothermal temperatures. An increase in heating temperature from 120 to 240 °C did not only enhance the saturation magnetization from 21 to 81 emu g⁻¹ but also produced larger, highly crystalline cubic particles of FeNPs. The development of FeNPs-modified glassy carbon electrode (GCE) using Nafion as a binder for sildenafil (SIL) detection was studied. Cyclic voltammetry and differential pulse voltammetry methods were employed for the electrochemical analysis of SIL using the modified electrode. The proposed sensor exhibited excellent electrocatalytic activity towards SIL oxidation with an enhancement in oxidation peak current. Under the optimum conditions, the current response for the determination of SIL was linear in two concentration ranges of 1.33–9.20 and 9.20–80.76 ppm and the limit of detection was 1.01 ppm. This sensor was then used for the determination of SIL in real samples with satisfactory results.