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 degrees 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 x 10(-6) mol L-1 and 2.0 x 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. (C) 2014 Elsevier Ltd. All rights reserved.