Electrochemically reduced graphene oxide/gold nanoparticles composite modified screen-printed carbon electrode for effective electrocatalytic analysis of nitrite in foods

Via a single-step electroreduction, the electrochemically reduced graphene oxide/gold nanoparticles (ERGO/AuNPs) composite was prepared on a disposable screen-printed carbon electrode (SPCE) for nitrite sensing. The AuNPs can be well dispersed in the stacked and wrinkled ERGO sheets. The possible mechanism for forming the unique structure of the hybrid composite was proposed. The electrochemical studies showed that AuNPs were efficient electrocatalysts towards the oxidation of nitrite, while the winkled ERGO sheets provide a 3D network scaffold for attachment of AuNPs and absorption of abundant nitrite, and promote the rapid heterogeneous electron transfer. The optimization of electrochemical reaction conditions also has been performed. The optimized electrode exhibited excellent properties for the detection of nitrite, including a low oxidation potential (0.65 V), wide linear range (1–6000 μM), high sensitivity (0.3048 μA μM−1 cm−2), low detection limit of 0.13 μM (S/N = 3), and great selectivity. Moreover, the good accuracy and recovery of ERGO/AuNPs based electrochemical sensor were achieved in the analysis of nitrite in various real food samples.