An amperometric sensor for nitric oxide based on a glassy carbon electrode modified with graphene, Nafion, and electrodeposited gold nanoparticles

This article describes the fabrication of a glassy carbon electrode (GCE) modified with a film containing graphene and gold nanoparticles (AuNPs) that can be used for the determination of nitric oxide (NO) at pH 7.0. A layer of gold nanoparticles was first deposited on the GCE, this followed by coating it with a film of graphene and Nafion. The response of the electrode to NO was studied by cyclic voltammetry and amperometry. A sharp anodic peak was observed at 0.81 V, and the anodic peak current was largely increased compared to a bare GCE or a mono-film modified GCE. A negative shift of the anodic peak potential (by 220 mV) indicates that the composite film has a beneficial effect on ease of the electrochemical oxidation of NO. The electron transfer number was calculated from chronocoulometric data. The amperometric response to NO is linear in the 36 nM to 20 μM concentration range (with a correlation coefficient of 0.9981), and the detection limit is 18 nM (at a S/N of 3). The release of NO from the fish liver homogenate stimulated by L-arginine was studied with this electrode.