Application of Single-Walled Carbon Nanotubes/Au Nanosol Modified Electrode for the Electrochemical Determination of Esculetin in Cortex Fraxini

A novel simple, sensitive and selective electrochemical sensor was successfully prepared for the determination of esculetin in Cortex Fraxini based on the carboxylic acid-functionalized single-walled carbon nanotubes-Nafion–Au nanosol nanocomposite modified glassy carbon electrode (c-SWCNTs-NF–AuNs/GCE). Scanning electron microscopy, energy dispersive X-ray spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry were carried out to characterize the properties of c-SWCNTs-NF–AuNs nanocomposite. Owing to the synergistic effects of large surface area, superior electrical conductivity, and large amount of chemically active sites of c-SWCNTs, together with the good biocompatibility and high conductivity of AuNs, the c-SWCNTs-NF– AuNs/GCE exhibited a good electrocatalytic activity to esculetin with wide linear range of 0.004–55 μM and low detection limit of 0.12 nM. Additionally, the modified electrode was employed for analysis of esculetin in Cortex Fraxini with satisfactory results.