Integrated sensor platform for real-time monitoring of nitrate, ammonium, temperature, and pH in aquatic environments

Authors: INAM, WARWAR - University Of Texas; RIAM, SHAD - University Of Texas; ISLAM, MD - University Of Texas; GALIB, ALI - University Of Texas; SANGMEN, ELVIS - University Of Texas; Ott, Brian; TABASSUM, SHAWANA - University Of Texas

Submitted to: Talanta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2025
Publication Date: N/A
Citation: N/A
DOI: https://doi.org/10.1016/j.talanta.2025.128466

Interpretive Summary: Aquaculture systems are dynamic environments with water quality parameters that can change every hour. Continuous monitoring of water quality in aquaculture systems is challenging and requires expensive specialized equipment. In this study, we developed a low-cost sensor platform to measure ammonium, nitrate, temperature, and pH in water. All sensor elements were integrated onto a single flexible sbustrate and protected by a 3D-printed waterproof housing. The nitrate and ammonium sensors utilized customized copper (Cu) and polyaniline (PANI) electrodes, respectively, that have a detection range from 1 to 100 mg N/L for nitrate and 0.05–10 mg N/L for ammonium. Additionally, real-time measurements of temperature and pH improve accuracy by compensating for environmental changes that affect ion detection. The sensors demonstrated 83% accuracy when compared to measurements from commercial kits. The integration of all four measurements in a small, low-cost footprint, makes this device a valuable tool in monitoring aquaculture water quality.

Technical Abstract: This study reports the development and characterization of an integrated electrochemical sensor platform for real-time, simultaneous detection of nitrate, ammonium, temperature, and pH in aquatic environments. The nitrate and ammonium sensors utilized customized copper (Cu) and polyaniline (PANI) electrodes, respectively, which exhibited high sensitivity within a detection range from 1 to 100 mg/L for nitrate and 0.05–10 mg/L for ammonium. Calibration plots revealed excellent linear response for both sensors (R² = 0.98), with detection limits of 0.84 mg/L for nitrate and 0.02 mg/L for ammonium. This platform is distinguished by its multi- parameter detection capability, where real-time measurements of temperature and pH offer contextual accuracy in ion measurements by compensating for environmental changes that affect ion detection. The results indicate robust selectivity and stability against common interferents in water, demonstrating this platform’s reliability for on-site environmental monitoring. The integration of all sensor elements onto a single flexible substrate, combined with encapsulation in a waterproof 3D-printed housing, enables field applications and continuous data collection, with real-time transmission to a remote server for monitoring. This integrated system was deployed in a recirculating aquaculture system to monitor nitrate and ammonium levels over a 24-h period. The sensors demonstrated high accuracy when compared to commercial test kits, with a root mean square error of 2.64 mg/L NO3-N (R² = 0.83) for the nitrate sensor and 0.41 mg/L NH4–N (R² = 0.84) for the ammonium sensor. Hence, this multi-parametric platform represents an innovative step forward for sustainable, accurate, and precise water quality assessment for aquacultural and environmental management applications.