Ultrasonication–dry-based synthesis of gold nanoparticle-supported CuFe on rGO nanosheets for competent detection of biological molecules

This study details the synthesis of gold (Au) nanoparticle-supported copper ferrite (CF) over reduced graphene oxide (Au-CF@rGO) through ultrasonication–dry synthesis techniques. The vigorous stormy mixing and acoustic cavitation acquired from the intense shock waves produced during ultrasonication can effectively irradiate the reaction conditions. The as-synthesized nanoparticles exhibit excellent crystallinity as well as homogeneous distribution over rGO nanosheets, as established by XRD, HR-TEM, Raman, XPS, and EDX analysis. Furthermore, the electrochemical analysis by cyclic voltammetry and differential pulse voltammetry (DPV) technique was accomplished by fabricating an Au-CF@rGO/GCE modified electrode. Interestingly, the DPV studies of the modified Au-CF@rGO/GCE electrode detects the dopamine (DA) in the linear concentration ranges from 0.001 to 119.6 µM, a low detection limit of 0.001 µM, a limit of detection of 0.34 nM, and enhanced sensitivity of 8.743 µAµM⁻¹cm⁻². The excellent electrochemical property towards the detection of DA indicates the successful formation of strongly anchored Au-CF nanoparticles on rGO nanosheets. Conversely, the modified Au-CF@rGO/GCE electrode shows excellent reproducibility, repeatability, and selectivity with excellent storage stability. In addition, the electrochemical sensor was used to examine real samples to determine the amount of DA present in commercially available banana milk samples, with a sensing efficiency of approximately 99%.