Spectrophotometric Determination of Nitrite in Aqueous Solution by the Diazotization-Coupling Method with Orthanilic Acid-Resorcinol |
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Authors: | W. A. Bashir S. Flamerz Saad Khlil Ibrahim |
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Affiliation: | 1. Department of Chemistry, College of Science , University of Mosul , Mosul, Iraq;2. Department of Chemistry and Biology , College of Education, University of Mosul , Mosul, Iraq |
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Abstract: | Abstract A spectrophotometric method for the determination of nitrite is described. It relies upon the reaction of this ion with an acidified orthanilic acid solution to form a diazonium ion, which is subsequently coupled with resorcinol, in alkaline medium, to form immediately a yellow-colored stable water-soluble and intense azo dye having maximum absorption at 426 nm. The linear absorbance plot with concentration indicates that Beer's law is obeyed over the range of 1-12 μg of nitrite in a final volume of 10ml, with a molar absorptivity of 38.7 × 1031 mol?1cm?1, sensitivity index of 0.0012μgcm?3, relative error of –0.5 to +0.2% and relative standard deviation of 0.43-3.5%, depending on the concentration level. The optimum conditions affecting and related to the color reaction and interference due to foreign ions have been studied. |
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Keywords: | Nitrite determination aqueous solution spectrophotometry diazotization-coupling method orthanilic acid-resorcinol. |
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