Electrochemical determination of quercetin using glassy carbon electrode modified with WS/GdCoO nanocomposite.

A WS/GdCoO nanocomposite was successfully prepared using hydrothermal-assisted synthesis. Our prepared WS/GdCoO nanocomposite was fabricated on a glassy carbon electrode (GCE) for the detection of quercetin (QCT). The WS/GdCoO nanomaterial was characterized by powder XRD, micro-Raman, FT-IR, XPS, FE-SEM, and HR-TEM, which proved that WS nanoplates were finely dispersed on the surface of the GdCoO nanoflakes. The electrocatalytic performance of WS/GdCoO was investigated by the EIS technique, and it exhibited a small semi-circle, which confirms that it has a large active surface area and high electrical conductivity. The electrochemical behavior of QCT at the WS/GdCoO sensor was explored by using the CV and DPV methods. The proposed electrochemical sensor exhibited excellent electrochemical response toward QCT with a wide linear range of 0.001 to 329 µM, low limit of detection (LOD) of 0.003 µM, and limit of quantification (LOQ) of 0.0101 µM. The sensor also displayed excellent selectivity, sensitivity, reproducibility, and stability. Additionally, the WS/GdCoO sensor was utilized for the detection of QCT in apple juice and grape juice samples, and it exhibited good recovery results.