నైరూప్య

Quantitation of trace amounts of nitrite in water samples using 4- amino-3-hydroxynaphthalene-1-sulfonic acid and central composite design

Masoud Shariati-Rad, Mohsen Irandoust, FarahnazNiazi

A simple, selective and very sensitivemethod for the spectrophotometric determination of nitrite in water has been developed and optimumreaction conditions alongwith other analytical parameters have been evaluated. Optimum conditions of the factors influencing the reaction were explored by central composite design (CCD). The variables chosen were pHof the acidic solution and volume of 4-amino-3-hydroxynaphthalene- 1-sulfonic acid. The method is based on the reaction of nitrite with 4- amino-3-hydroxynaphthalene-1-sulfonic acid.The absorbance of the product at 303 nm obeyed BeerÂ’s law in the concentration range of 0.001- 0.200 mg L-1 of nitrite.Adetection limit of 5×10-4 mg L-1 was obtained for the determination of nitrite by the proposedmethod. Themethod was successfully applied to determine nitrite inwater sample. The RSDof the method for determination of nitrite inwater sampleswas 6%. Themethod is capable in determination of trace amounts of nitrite in water samples.