Gadolinium (III) Tungstate Nanoparticles Modified Carbon Paste Electrode for Determination of Progesterone Using FFT Square-Wave Voltammetry Method

Gadolinium (III) tungstate nanoparticles (Gd ₂ (WO ₄ ) ₃ NPs) modified carbon paste electrode (CPE) was constructed and the electrocatalytic properties of the NPs-modified electrode toward the reduction of progesterone (P4) were analyzed. In relation to the Gd ₂ (WO ₄ ) ₃ NPs, wolframite structure, adsorption of P4 on the electrode surface occurred, which was characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Determination of P4 was performed with stripping cyclic voltammetry (CV) and fast Fourier transformation square-wave voltammetry (FFT-SWV) in 0.1 M Britton–Robinson buffer (BRB) solution at pH 11.5. On the other hand, participation of equal numbers of electrons and protons in the reduction reaction of P4 was observed. A reduction peak current at −1.35 V of P4 was obtained, which increased linearly with the P4 concentration in the range of 0.1 to 1.0 μ M (R ² = 0.972), with higher sensitivity of 485.64 μ A μ M ⁻¹ and a limit of detection (LOD) being 50 nM. Common hormones showed no obvious interference with the P4 biosensor’s response. Finally, the presented method was able to determine P4 simply and effectively in human blood plasma sample.