Electrochemical detection of nitrite based on glassy carbon electrode modified with gold-polyaniline-graphene nanocomposites

First, polyaniline-graphene oxide (GO-PANI) nanocomposites were prepared by the in situ polymerization of aniline in the presence of graphene oxide (GO). Next, the GO-PANI nanocomposites were reduced to polyaniline-graphene (G-PANI) nanocomposites by a green electrochemical reduction method. Finally, a thin layer of nearly monodispersed Au nanoparticles with a uniform size (similar to 12 nm) was coated on the surface of the G-PANI nanocomposites. Moreover, the as-prepared Au-polyaniline-graphene (Au-G-PANI) nanocomposites can be used as a sensing electrode material for the electrochemical detection of nitrite (NO2-). Compared with other common modified electrodes, the Au-G-PANI/GCE shows an obvious oxidation peak of NO2- with a larger peak current, and gives a wider linear range from 0.1 to 200 mmol L-1, with a detection limit of 0.01 mmol L-1 (S/N = 3). Besides, the oxidation process of NO2- on the Au-G-PANI/GCE is proven to be a surface-controlled process involving the transfer of two electrons. The present study widens the applications of graphene-based nanocomposite materials in the electrochemical detection of environmental pollutants.