Gold Nanoparticle-Modified Electrodes for Electrochemical Sensing of Ammonia Nitrogen in Water

As a common water pollutant, ammonia nitrogen (aN) has adverse effects on human life and production. Therefore, it is of great significance to realize the precision prevention of aN. Here, gold nanoparticle (AuNP)-modified carbon cloth (CC) electrodes were prepared for aN detection using cyclic voltammetry (CV). The first electrode was synthesized by in situ loading of AuNPs on the flexible CC (AuNPs/CC), and the second electrode was obtained by deposition of graphene coating on this basis (AuNPs/CC@G). Their selective response to aN was attributed to the formation and transformation of the gold ammonia complex through the electrodissolution of AuNPs. Two electrodes had a wide quantitative range (0.001–10000 μM); meanwhile, the limits of detection (LoDs) were down to the nanomolar level. From the aN standard to a real water sample, both nanocomposite electrodes also exhibited excellent sensing performance in the aspect of anti-interference, reusability, reproducibility, stability, and recovery. In the simultaneous comparison, the superior results of AuNPs/CC@G have confirmed the realization of optimization, which provided an innovative solution for the efficient and accurate monitoring of aN in water.