Abstract
Nitrate reacts with 2-phenylbenzothiazole in concentrated sulfuric acid to form 6-nitro-2-phenylbenzothiazole, which changes to 6-amino-2-phenylbenzothiazole by the irradiation with ultraviolet light in an ammoniacal dioxane solution and the 6-amino-2-phenylbenzothiazole gives the intense fluorescence with excitation maximum at 358 nm and emission maximum at 457nm. By using this reaction, 0.01-3.0μg/ml of nitrate ion can be determined fluorophotometrically. In the application of this method for the analysis of tap water, the interferences from nitrite ion, residual chlorine and chloride ion can be eliminated by using sulfamic acid, sodium sulfite and silver sulfate, respectively.
