Spectrophotometric determination of ammonia with chloramine T and thymol

Collection of Indonaphthol Blue on a Membrane Filter for the Spectrophotometric Determination of Ammonia with 1-Naphthol and Dichloroisocyanurate

“…In this study, we chose 1-naphthol because it was the only reagent that formed the blue compound without adding nitroprusside and collected on the membrane filter as an ion pair with Zephiramine. Instead of sodium hypochlorite, we examined the stable powder reagents DIC 4,5 and chloramine-T. 10 We chose DIC because it was more sensitive than chloramine-T in the Berthelot reaction.…”

“…In these methods, however, the addition of nitroprusside is indispensable for these color development. Methods using thymol, [10][11][12][13][14][15] instead of phenol, were also reported. In these methods, the addition of acetone and the use of solid-phase extraction are performed to obtain high sensitivity.…”

“…In the methods, however, the reaction time for the color development was as long as 60 min. 10,11 Or, to reduce the reaction time, nitroprusside had to be used. [12][13][14][15] Modified Berthelot reactions using 1-naphthol, instead of phenol, were developed, [16][17][18][19] including our report which performed flow injection analysis.…”