title: Reversed flow injection spectrophotometric determination of trace amount of ammonia in natural water by oxidation of ammonia to nitrite.
abstract: A new sensitive flow injection method for determination of ammonia in natural water samples have been developed, based on the oxidation of ammonia to nitrite by hypochlorite in the presence of large amount of potassium bromide. The oxidant solution obtained by on-line mixing of hypochlorite and potassium bromide was injected into a water carrier stream, and then mixed with sample stream. Ammonia in the sample solution was oxidized to nitrite. Nitrite was then determined by spectrophotometry with sulfanilamide and N-1-naphthylethylenediamine. By reversed injection of the oxidant solution, the interference of nitrite and turbidity of the sample can be removed. The linear range of the method for ammonia is 0.2-12 muM. The proposed method is simple and sensitive. It had been applied to the determination of ammonia in lake water samples. Recoveries of 95-104% were obtained.
authors.affiliation: Department of Chemistry, Liaocheng Teachers College, Liaocheng, Shandong 252059, People's Republic of China.
authors.forename: R
authors.initials: R
authors.lastname: Liu
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: A
authors.initials: A
authors.lastname: Sun
authors.forename: D
authors.initials: D
authors.lastname: Liu