Highly sensitive electrochemical sensor for paeonol using NMP-exfoliated grapheme-modified electrode

Graphene nanosheets (GS) were easily prepared from graphite powder by one-step ultrasonic exfoliation in N-methyl-2-pyrrolidone (NMP). The resulting GS was used to modify the surface of glassy carbon electrode (GCE) via solvent evaporation. The electrochemical behaviors of paeonol were studied, and a sensitive oxidation peak of paeonol was observed on the GS-modified GCE (GS/GCE). Compared with the unmodified GCE, the GS/GCE greatly enhanced the oxidation signals of paeonol, showing remarkable signal enhancement effects. The influences of pH values, amount of GS, accumulation potential, and time were examined on the oxidation peak currents of paeonol. As a result, a highly sensitive electrochemical sensor was developed for paeonol. The linear range was over the range from 0.1 to 15 μM, and the detection limit was calculated to be 32 nM. The proposed method was used in the sample analysis of cortex moutan, and the detected results consisted with the values of that obtained by high-performance liquid chromatography.