Colorimetric Determination of Ammonia. IV. A New Method with o-Chlorophenol and 2, 6-Dichloroisocyanurate

Abstract

Use of o-chlorophenol instead of salicylate improved the sensitivity of salicylate-2, 6-dichloroisocyanurate method for the determination of ammonia. By the use of 2, 6-dichloroisocyanurate, the stored oxidant solution became more stable than sodium hypochlorite, which had been commonly used up to now. The presence of a micro-amount of sodium nitroprusside was necessary. Apparent molar extinction coefficient on the basis of nitrogen atom and coefficient of variation at 15.15μg/ml ammonium sulfate were 3.14×10⁴ and 1.83%, respectively. Absorbance of the reagent blank at 665 mμ was as low as 0.058±0.005.