Possible Influences on Ammonia Nitrogen Determination by Nessler's Reagent Spectrophotometry

摘要

Nessler's reagent spectrophotometry is the traditional method for ammonia nitrogen (NH 3 -N) determination, which is adopted in the national standard of the People's Republic of China (HJ 535-2009). In order to improve the accuracy of such method, possible influences, Nessler's Reagent preparation, pH value of the solution, metal ions, organic solvents and natural organic matters, on NH 3 -N determination were discussed. The results suggested that the method B, employing KI, HgI 2 and NaOH, is preferred in Nessler's Reagent preparation. And the Nessler's Reagent Spectrophotometry may be executed over a wide pH range (4-11). The metal ions, organic solvents and natural organic matters have significant influences in NH 3 -N detection.