Document Type : Research Paper
Authors
Department of Analytical Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Iran
Abstract
A simple and rapid spectrophotometric method for the determination of nitrite in water and soil preparation samples has been developed. Determination of nitrite is based on diazotization of p-nitro aniline with nitrite and subsequent coupling with 4-amino-3-hydroxynaphthalene-1-sulfonic acid in hydrochloric acid. The factors affecting the reaction i.e. concentration of p-nitro aniline, concentration of 4-amino-3-hydroxynaphthalene-1-sulfonic acid and concentration of the hydrochloric acid solution were studied and optimized using central composite design. The analysis of the results of experimental design showed that for obtaining higher signals the values of the above factors should be as 2.0×10-4, 5.0×10-4 and 1.33 M, respectively. The reaction yields a product with an absorption maximum at 302 nm. Beer’s law is obeyed in the range 0.10-2.00 mgL-1 of nitrite. The molar absorptivity of the product was found to be 6.74×104. The method was applied successfully to the determination of nitrite in water and soil samples. Relative standard deviation of the method was below 2%.
Keywords
Abbas M.N., Mostafa G.A., Determination of traces of nitrite and nitrate in water by solid phase spectrophotometry, Analytica Chimica Acta 410 (2000) 185-192.
Black J.A., Water Pollution Technology, Reston Publishing Co., Reston, VA, 1977, p. 189.
Burden E. H. W. J., The toxicology of nitrates and nitrites with particular reference to the potability of water supplies. A review, Analyst 86 (1961) 429-433.
Box G. E. P., Hunter J. S., Multi-factor experimental designs for exploring response surfaces, Annals of Mathematics and Statistics 28 (1957) 195-241.
Box G.E.P., Hunter W. G., Hunter J.S., Statistics for Experimenters: An Introduction to Design, Data Analysis and Model Building, John Wiley, 1978, p. 534.
Box G. E. P., Wilson K. B., Roy J., On the experimental attainment of optimum conditions, Statist. Soc. Ser. B Method., 13 (1952) 1-45.
Cortes H.J., High-performance liquid chromatography of inorganic and organic anions using ultraviolet detection and an amino column, Journal of Chromatography 234 (1982) 517–520.
Crowther D., Monaghan J.M., Cook K., Gara D., Nitrate and nitrite determination in complex matrices by gradient ion chromatography, Anal. Commum., 33 (1996) 51-52.
Filik H., Giray D., Ceylan B., Apak R., A novel fiber optic spectrophotometric determination of nitrite using Safranin O and cloud point extraction, Talanta 85 (2011) 1818–1824.
Glidewell C., (1990) The nitrate/nitrite controversy, Chem. Britain, 26 (1990) 137-140.
Greiss J.P., Bemerkungen Z.A.H.H., Ueber einige Azoverbindungen, Berichte der Deutschen Chemischen Gesellschaft 12 (1897) 426-428.
Gunaraj V., Murugan N., Application of response surface methodology for predicting weld bead quality in submerged arc welding of pipes, Journal of Materials Processing Technology 88 (1999) 266–275.
Gao Z., Wang G., Zhao Z., Determination of trace amounts of nitrite by single-sweep polarography, Analytica Chimica Acta 230 (1990) 105-112.
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