Determination of Permanganate Index in Source Water and Drinking Water by Ammonium Ferrous Sulfate Spectrophotometry

Objective To develop a method to determine permanganate index in source water and drinking water by ammonium ferrous sulfate spectrophotometry.

Methods The 2 mL water sample and 0.2 mL KMnO₄ standard solution were added into a vial, which was heated at 100℃ for 30 min in a thermostatic digester. After cooling rapidly, 0.2 mL ammonium ferrous sulfate solution was added into the vial and mixed. Then the sample was colorized with 5 mL phenanthroline indicator solution. The permanganate index was measured by spectrophotometer at 510 nm.

Results The determined limits for permanganate index in drinking water was 0.50 mg/L. The average recoveries were from 99.2% to 107.2%, and the relative standard deviations ranged from 0.20% to 0.66%. The result of national certified standard substances (GSB07-3162-2014) by this method was within the range of quality control.

Conclusion The method established in this paper has the characteristics of good precision and accuracy, simple operation, time-saving and labor-saving, which was more suitable for the analysis permanganate index in source water and drinking water.