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

A fully automated spectrophotometric analyzer for continuous, unattended de termination of inorganic nitrogen (nitrite, nitrate, and ammonia) was devel oped. The analysis involves online UV photo-induced conversion of nitrate t o nitrite and chemical oxidation of ammonia to nitrite. In both cases, nitr ite was then subsequently determined by spectrophotometry using the sulfani lamide and N-1-naphthyl-ethylenediamine color reagents. Experimental condit ions investigated to optimize the determination of nitrate and ammonia are presented. The linear ranges of the methods for nitrate and ammonia are 0.0 1-14 ppm and 0.01-5 ppm, respectively The proposed method is simple, low co st, and sensitive. The analyzer was operated automatically and unattended f or a period of 30 days. (C) 2000 John Wiley & Sons, Inc.