Simple spectrophotometric method for the determination of sulfur dioxide by its decolorizing effect on the peroxovanadate complex |
| |
Authors: | Mahadevaiah M S Abdul Galil M S Yogendra Kumar M A Sathish G Nagendrappa |
| |
Institution: | (1) Department of Chemistry, University of Mysore, Manasagangotri, Mysore, 570006, India |
| |
Abstract: | A simple, rapid, and economical spectrophotometric method is developed for the determination of sulfur dioxide in sugar and
air samples. The developed method is based on a red-brown peroxovanadate complex (λmax = 470 nm) produced in 2 M sulfuric acid when ammonium metavanadate is treated with hydrogen peroxide. Under fixed concentrations
of hydrogen peroxide and ammonium metavanadate, when sodium metabisulfite (Na2S2O5 = 2SO2) is added, it preferentially reacts with hydrogen peroxide producing sulfuric acid, and the unreacted hydrogen peroxide then
reacts with ammonium metavanadate; therefore, the concentration of sulfur dioxide is directly proportional to a decrease in
the concentration of the peroxovanadate complex. The stoichiometric ratio between hydrogen peroxide and ammonium metavanadate
as well as the stability constant of the complex are determined by the modified Job’s method and the respective values are
found to be 1: 1 and 2.5 × 104 mol−1 L, respectively. The system obeys Lambert-Beer’s law in the concentration range 3.57–64.26 ppm of sulfur dioxide. The molar
absorptivity, correlation coefficient, and Sandell’s sensitivity values are found to be 0.649 × 103 L mol−1 cm−1, 0.9908, and 0.1972 μg cm−2, respectively. The method is applied to the determination of sulfur dioxide present in commercial sugars and air samples.
The results obtained are reproducible with a standard deviation of 0.02–0.05. For method validation, sulfur dioxide is also
determined separately following the AOAC method for an air sample and the ICUMSA method for commercial sugars. The results
obtained by the developed and official methods are in good agreement.
The text was submitted by the authors in English. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|