Facile preparation of metal-free graphitic-like carbon nitride/graphene oxide composite for simultaneous determination of uric acid and dopamine

Graphitic-like carbon nitride/graphene oxide composite nanosheets (g-C3N4/GO) were synthesized for simul-taneous determination of uric acid (UA) and dopamine (DA). The surface features and electrochemical properties of the g-C3N4/GO were investigated by scanning electron microscopy, X-ray diffraction, cyclic voltammetry and electrochemical impedance spectra. The voltammetric responses of UA and DA were determinated by cyclic voltammetry and differential pulse voltammetry. g-C3N4/GO had significantly improved electrical conductivity, selective oxidation capacity and electrocatalytic activity. The proposed g-C3N4/GO modified glassy carbon electrode (GCE) consequently displayed excellent electrocatalytic activity for UA and DA, with a broad linear detection range (0.03-30 mu M) and extremely low detection limits (UA 4.6 nM; DA 5.4 nM). The proposed g-C3N4/ GO/GCE also demonstrated excellent reproducibility, selectivity and stability. The levels of UA and DA in human serum were measured by the g-C3N4/GO/GCE, and then the known concentrations of UA and DA were spiked to the samples, which proved that the recoveries were good.

Automated summary

Graphitic-like carbon nitride/graphene oxide composite nanosheets (g-C3N4/GO) were synthesized and used for simultaneous determination of uric acid (UA) and dopamine (DA). The g-C3N4/GO exhibited improved electrical conductivity, selective oxidation capacity and electrocatalytic activity. The modified glassy carbon electrode (GCE) showed excellent electrocatalytic activity for UA and DA with a wide linear detection range and low detection limits. The g-C3N4/GO/GCE also demonstrated good reproducibility, selectivity and stability.