Design of a In-situ Ammonia Nitrogen Analyzer in Seawater

A in-situ ammonia nitrogen analyzer in seawater was designed based on wet chemical reaction principle, combined the fluorospectrophotometry method with flow injection analysis. The analyzer was controlled by peristaltic pump and tree-way valve, which has the advantages of high sensitivity, low-reagent consumption and can measure the concentration of ammonia nitrogen in seawater in-situ. The detection range was 10 similar to 500 mu g/L, while the detection limit was 1.80 mu g/L and the relative standard deviation (RSD) was less than 2%. The on-site comparison tests between the ammonia nitrogen analyzer and the national standard methods were finished, and the results indicated that the analyzer was entirely feasible and could reflect the content and changes of the ammonia nitrogen in the seawater.