A novel 3D-CB/HEC-CH@Cu hybrid electrode for sensitive and rapid ammonia nitrogen detection in environmental water

In this paper, a electrode based on 3D-printed carbon black (3D-CB), and coated with a hydroxyethylcellulose/chitosan (HEC/CH) bilayer and finished by copper electrodeposition, is presented for the electrochemical sensing of ammonia nitrogen (AN) in water. Measurements were performed using square-wave voltammetry (SWV) in borate buffer (pH 9) under optimized conditions. The electrochemical method displayed good linear relationship between 0.7 and 20.4 mg L^-1 of AN with limits of detection (LOD) and quantitation (LOQ) of 0.014 and 0.043 mg L^-1 respectively, good precision (RSD ≤≃4.18% intra/inter-day, n = 10), and practical throughput (∼70 analyses per h). Accuracy in real waters was evaluated through standard-addition and spike-recovery experiments, yielding ∼99.8% recoveries. Statistical analysis was used to compare the obtained results to the expected values and no significant difference was observed between added and found concentrations. Therefore, the proposed 3D-CB/HEC-CH@Cu SWV method presents a viable alternative for the efficient, low-cost and safe determination of ammoniacal nitrogen in the water quality control process.