Application of Ammonia Nitrogen On-Line Monitor Based on Flow Injection

A method for online monitoring of ammonia nitrogen was developed using flow injection analysis system and the indophenol blue spectrophotometry. This method involves a simple solution of sodium dichloroisocyanurate as a substitute for the traditional sodium hypochlorite solution. The integrated flow injection analysis system was operated with laboratory programming software written in LabVIEW. On the basis of single factor design, various parameters for ammonia nitrogen determination were optimized. The research results showed that the system could determine ammonia nitrogen in river water, with a correlation coefficient of the standard curve reaching $\mathbf{0. 9 9 5 2}$. The recovery rate, precision, and accuracy were high, and it had the advantages of convenience, efficiency, speed, and high degree of automation. This approach is well-suited for both laboratory analysis and real-time monitoring of ammonia nitrogen.