[Catalysis-fluorescence determination of trace nitrite based on the oxidation of acridine orange by potassium bromate].

Acridine orange can be oxidized with discoloring and fluorescence quenching by potassium bromate in phosphoric acid medium, but the reaction rate is very low. The presence of trace nitrite can catalyze this reaction to improve the sensitivity of it apparently and to make the net fluorescence value of the system decrease greatly. Based on the above investigation, a new catalysis-fluorescence determination method of trace nitrite has been proposed. The method described is very sensitive and selective. The catalysis reaction is under the conditions of lambdaex/lambdaem = 446/505 nm, 55 degrees C and 10 min for the reaction time. The method permits the existence of more than 20 common foreign ions. There isn't interference by the same quantity of Fe3+, Br- and I-. The detection limit is 0.012 ng x mL(-1). The linear range of determination is 0.05-5 ng x mL(-1). The method has been used for the determination of trace nitrite in water and soil samples with satisfactory results.