Development of a fully automated inorganic nitrogen analyzer for continuous, unattended monitoring of water quality

摘要

A fully automated spectrophotometric analyzer for continuous, unattended determination of inorganic nitrogen (nitrite, nitrate, and ammonia) was developed. The analysis involves online UV photo-induced conversion of nitrate to nitrite and chemical oxidation of ammonia to nitrite. In both cases, nitrite was then subsequently determined by spectrophotometry using the sulfanilamide and N-1-naphthyl-ethylenediamine color reagents. Experimental conditions investigated to optimize the determination of nitrate and ammonia are presented. The linear ranges of the methods for nitrate and ammonia are 0.01-14 ppm and 0.01-5 ppm, respectively. The proposed method is simple, low cost, and sensitive. The analyzer was operated automatically and unattended for a period of 30 days.