Spectrophotometric Determination of Trace Amount of Ammonium Nitrogen in Water

Abstract

An examination was made on the sensitive spectrophotometric determination of ammonia-nitrogen in water. Ammonia was determined indirectly by measuring the blue complex produced by reaction with potassium iodide-starch reagent and chloramine compound, which was formed by the reaction of ammonia and hypochlorite at pH 5.4. Unreacted hypochlorite was destroyed with ferrous sulfate before addition of potassium iodide-starch reagent. The absorbance of developed color of the blue complex was measured at 570 mu. The method was applicable for the determination of ammonia-nitrogen in the range af 0.01 to 0. 4 ppm, at between 21 and 26°. The standard deviation was 2.2% on an average absorbance 3. 496 of a sample containing 0.2 ppm of ammonia-nitrogen. © 1972, The Pharmaceutical Society of Japan. All rights reserved.