Cadmium sulfide quantum dots anchored on reduced graphene oxide for the electrochemical detection of metronidazole

In this research, the metal–organic-based synthesis of cadmium sulfide quantum dots (CdS QDs) was performed. The CdS QDs were anchored on reduced graphene oxide (rGO) nanosheets using a simple sonication technique; this can enhance the electron charge transfer properties of the CdS QDs. The successful formation of the CdS QDs@rGO composite was revealed using various analytical techniques, such as X-ray diffractometry (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Optical and morphological analysis revealed that the composite took the form of a well-dispersed suspension. The as-prepared composite was fabricated on a glassy carbon electrode (GCE) for the electrochemical detection of metronidazole (MTZ). Owing to the synergistic effect between rGO and CdS QDs, a superior electrochemical response was obtained using cyclic voltammetry analysis. Quantitative analysis using the differential pulse voltammetry (DPV) technique revealed a wide linear MTZ concentration range from 0.1 to 203.1 μM with a low-level detection limit of 0.053 μM. Furthermore, the practical applicability of the proposed electrode was assessed in milk samples with satisfactory recovery results.