The Application Study Of Nitrogen Doped Three-dimensional Porous Graphene Modified Electrode As Electrochemical Sensor

A nitrogen doped three-dimensional porous graphene(NG) modified electrode was fabricated in our work. Epinephrine(EP) and Metanephrine(MEP) were dectected used the modified electrode as the biosensor. The work consists of two parts, and is summarized as follows:(1) The NG was dropped on the surface of GCE to prepare the NG-modified electrode(NG/CS/GCE). The electrochemical characterization carried by the voltammetric behavior of hexaammineruthenium chloride(Ru(NH3)6Cl3) showed that the redox peak currents were significantly enhanced at the modified electrode compared with that of bare GCE, which was ascribed to the excellent properties of NG. Furthermore, the SEM images of NG/CS/GCE indicated that, the NG dropped on the surface of GCE remained well-defined three-dimensional structure. Additionally, the Raman spectroscopy of NG revealed that there were structure defects on the graphene edges, which was related to the good electrocatalysis of NG/CS/GCE.(2) The electrochemical behavior of EP and MEP on NG/CS/GCE was studied, and the mechanisms of EP and MEP were proposed. The modified electrode was used for sensitive detection of EP and MEP. By differential pulse voltammetry, the anodic peak currents were linearly proportional to the concentrations from 1.0 ?M to 1.0 mM with a sensitivity of 0.021 ?A/?M for EP and 1.5 ?M to 0.41 mM with a sensitivity of 0.0095 ?A/?M for MEP. The detection limits were ascertained to be 0.67 ?M and 1.3 ?M for EP and MEP, respectively. Additionally, the detection of EP and MEP was possible in the presence of ascorbic acid and uric acid. The modified electrode showed good stability, reproducibility and repeatability, and was applied to the detection of EP and MEP in human plasma samples with recoveries from 98.9% to 100.9%, and EP hydrochloride injections with recoveries from 100.3% to 104.6%.