Spectrophotometric determination as permanganate following oxidation by peroxodisulphate

3 Spectrophotometric determination as permanganate following oxidation by peroxodisulphate 

Manganese ions are quantitatively oxidized to permanganate ions in acid solution by peroxodisulphate in the presence of silver ions acting cata-lytically  

The coloration of the permanganate ions, taken as a measure of the total manganese content of the water sample, is evaluated photometrically at 525 nm (absorption maxima at 528 and 548 nm). Beer s law applies in the concentration range from 0.6 to 25 mg/1. 

The method is directly applicable to drinking water, ground water and surface water, and to waste waters following mineralization. Concentrations between 0.05 and 5 mg/1 can be determined without dilution or concentration. 

Chloride ions, organic substances and more than 5 mg/1 iron ions have an interfering effect. 

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