Gold nanoparticle decorated polypyrrole/graphene oxide nanosheets as a modified electrode for simultaneous determination of ascorbic acid, dopamine and uric acid

Simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) is always of vital importance for clinical diagnosis and healthcare. Hereby, a gold nanoparticle decorated polypyrrole/graphene oxide composite on carbon fiber paper (AuNPs@GO/PPy/CFP) was facilely prepared via a two-step method. Instead of reducing GO to rGO for better conductivity, GO was combined with PPy retaining its abundant oxygen containing functional groups, which is in favor of electrochemical sensing. The as-prepared electrode was evaluated in the simultaneous determination of AA, DA and UA. During the electro-oxidation of these analytes, three well-defined peaks with low overpotentials at -0.02 V, +0.16 V and +0.28 V were observed on the modified electrode. The linear response ranges obtained were 10-1600 mu M, 0.2-60 mu M and 2-360 mu M with the corresponding detection limits of 2.43 mu M, 0.115 mu M and 1.68 mu M (signal/noise = 3), respectively, for AA, DA and UA. This indicates that the as-prepared electrode has an excellent catalytic capability and high selectivity for the simultaneous determination of AA, DA and UA. In addition, the modified electrode showed satisfactory results when applied in real samples, suggesting the promising potential of AuNPs@GO/PPy/CFP for practical application in complex biological systems.