MWCNTs-Fe2O3nanoparticle nanohybrid-based highly sensitive electrochemicalsensor for the detection of kaempferol in broccoli samples

This work reports an electrochemical sensor with a modified glassy carbon electrode for the detection of kaempferol. The method was tailored by the immobilization of multiwalled carbon nanotubes (MWCNTs) assimilated with Fe$_{2}$O$_{3}$ nanoparticles (NPs) onto the electrode surface to detect kaempferol using differential pulse voltammetry. Thermogravimetric, transmission electron microscopic, cyclic, and differential voltammetric techniques were employed to characterize the developed electrochemical sensor. The kaempferol produces an anodic quasireversible peak at pH 6.6 in phosphate buffer with Fe$_{2}$O$_{3}$NPs/MWCNTs/GCE. The current of the anodic peak at 0.32 V increases linearly upon addition of kaempferol standard, resulting in Ip($\mu $A) = 1.577($\mu $M) $+$ 1.347 (R$^{2}$ = 0.9930). The limits of detection and limits of quantification were found to be 0.53 $\mu $M and 1.73 $\mu $M, respectively. Upon quantitative analysis of kaempferol in broccoli samples, it was found to be 3.78 $\mu $g g$^{-1}$ with an average percent recovery of 99.55%. The findings of this study identify the efficient catalytic property as a major contributor in the electron-transferring capacity from the electrode surface to the analyte, with promising possibilities of designing a highly sensitive electrochemical sensor for food industry applications.