Selection of Working Electrodes for the Electrochemical Determination of Ammonium and Nitrate in Aquaculture Water

Abstract

This study presents the selection and evaluation of ammonium and nitrate working electrodes  for integration into a multifunctional electrochemical system  to determine these parameters effectively. The electrochemical method employing selected ammonium and nitrate electrodes was evaluated based on key analytical parameters, including repeatability and the linear correlation between potential U (mV) and lgC (ppm) for both ions.  The research results showed that, the calibration curve for lgC_NH4+ (mg/L) versus potential U (mV) was described by the equation y = 0.6280x + 1.353, with a regression coefficient R² = 0.997; limit of detection (LOD) = 0.2922 mg/L; and limit of quantification (LOQ) = 0.8766 mg/L. The calibration curve for lgC_NO3- (mg/L) was y = 0.5420x + 2.067, with R² = 0.996; LOD = 0.3495 mg/L; and LOQ = 1.0485 mg/L.  The method demonstrated suitable detection and quantification limits for monitoring and providing rapid feedback on parameter fluctuations. Measurement accuracy was further validated through comparison with reference methods. Comparison with reference methods showed no significant differences between analytical approaches. Real-time, on-site electrochemical measurements conducted in aquaculture environments confirmed the suitability of the integrated sensors. All measured parameters were within permissible thresholds for freshwater aquaculture, demonstrating the practical utility and reliability of the system.