Direct electrochemistry and electrocatalysis of lobetyolin via magnetic functionalized reduced graphene oxide film fabricated electrochemical sensor

•The MrGO/Nafion@GCE electrochemical sensor was successfully fabricated.•The prepared MrGO was characterized by AFM, XRD, FTIR, VSM, TEM and SEM.•The proposed electrochemical sensor exhibited a broad detection range and low detection limit for lobetyolin.•The electrochemical sensor can be used for the sensitive and efficient analysis of lobetyolin in real samples.

A novel lobetyolin electrochemical sensor based on a magnetic functionalized reduced graphene oxide/Nafion nanohybrid film has been introduced in this work. The magnetic functionalized reduced graphene oxide was characterized by fourier transform infrared spectroscopy, atomic force microscope, X-ray diffraction, transmission electron microscopy and thermogravimetric analysis. The scanning electron microscopy characterized the morphology and microstructure of the prepared sensors, and the electrochemical effective surface areas of the prepared sensors were also calculated by chronocoulometry method. The electrochemical behavior of lobetyolin on the magnetic functionalized reduced graphene oxide/Nafion nanohybrid modified glassy carbon electrode was investigated by cyclic voltammetry and differential pulse voltammetry in a phosphate buffer solution of pH 6.0. The electron-transfer coefficient (α), electron transfer number (n), and electrode reaction rate constant (Κs) were calculated as 0.78, 0.73, and 4.63 s− 1, respectively. Under the optimized conditions, the sensor based on magnetic functionalized reduced graphene oxide/Nafion showed a linear voltammetric response to the lobetyolin concentration at 1.0 × 10− 7 to 1.0 × 10− 4 mol/L with detection limit (S/N = 3)of 4.3 × 10− 8 mol/L. The proposed sensor also displayed acceptable reproducibility, long-term stability, and high selectivity, and performs well for analysis of lobetyolin in real samples. The voltammetric sensor was successfully applied to detect lobetyolin in Codonopsis pilosula with recovery values in the range of 96.12% -102.66%.

Graphical abstractSchematic diagram of the synthesis of MrGO hybrid and the fabrication process of the MrGO/Nafion/GCE for determination of lobetyolin.Download high-res image (93KB)Download full-size image