Novel water-soluble multi-nanopore graphene modified glassy carbon electrode for simultaneous determination of dopamine and uric acid in the presence of ascorbic acid

A novel graphene-based nanomaterial, multi-nanopore graphene (mp-GR), modified glassy carbon electrode (mp-GR/GCE) is prepared for the simultaneous determination of dopamine (DA) and uric acid (UA) in the presence of ascorbic acid (AA). After a hydrothermal reaction of the graphene oxide in the presence of H2O2 at 180 °C for 2 h, the water-soluble mp-GR is obtained from the hydrothermal suspension. This mp-GR exhibits abundant carboxylic and/or hydroxide groups, edges, and defective sites due to the reaction and structure disruption caused by the hydrothermal treatment. The mp-GR appears an enhanced electrocatalytic activity toward DA and UA due to the unique structure and composition. The oxidation peak current of DA at the mp-GR/GCE is about 2.70 and 8.61 times higher than at the GR/GCE and the GCE, respectively. Using the mp-GR/GCE, the simultaneous differential pulse voltammetry determination of DA and UA in the presence of AA is successfully carried out, the detection limits (S/N = 3) for DA and UA are 1.5 × 10−6 mol L−1 and 2.0 × 10−6 mol L−1, respectively. In addition, this mp-GR/GCE exhibits high selectivity, reproducibility, and stability, and also can detect DA and UA in real human blood serum, showing its promising application in the electroanalysis of real samples.