Synergistic micrometer flower bloom: Quercetin electrochemical sensing platform constructed from CuO-C/NiCo2O4 composite material

Abstract

The pharmacological, biological, and biochemical properties of quercetin hold significant implications in the realms of medicinal chemistry, biochemistry, and clinical medicine. In this study, metal–organic framework (Cu-MOF), nickel nitrate, and cobalt nitrate were used as raw materials, and metal-oxide (CuO-C/NiCo₂O₄) composites containing carbonaceous and floral structures were prepared by annealing and co-precipitation techniques. The CuO-C/NiCo₂O₄/GCE composite electrode was acquired by embellishing CuO-C/NiCo₂O₄ on polished glassy carbon electrodes (GCE) using dropwise coating. The synthesized CuO-C/NiCo₂O₄ was investigated through: (i) scanning electron microscopy (SEM) imaging for morphological evaluation, (ii) X-ray diffraction (XRD) for phase identification, and (iii) X-ray photoelectron spectroscopy (XPS) for elemental state determination. The results revealed that the CuO-C/NiCo₂O₄ composites have a loose and porous surface, an elevated active surface area, high electrical conductivity, and electrocatalytic properties. Based on this result, an electrochemically novel sensor for the detection of quercetin using CuO-C/NiCo₂O₄ composites was developed. The sensor displayed high reproducibility, redox stability, and anti-interference capability in the detection of quercetin. In addition, the peak current measured by this sensor was linearly correlated with the density of quercetin, exhibiting a wide linearity response from 0.1 to 20 μM with an ultralow detection limit of 0.092 μM. These advantages originate in the synergy between CuO-C and NiCo₂O₄. Currently, the constructed electrochemical sensor has been successfully employed for the determination of quercetin content in ginkgo biloba leaf.