规定方法的原理是在沸水浴中用已知量的高锰酸钾和硫酸加热样品一段固定时间（10分钟），用样品中的可氧化物质还原部分高锰酸钾，并通过添加过量的草酸盐溶液测定消耗的高锰酸钾，然后用高锰酸钾滴定。适用于氯离子浓度低于300 mg/l的水。高锰酸盐指数超过10 mg/l的样品应在分析前稀释。试验的最佳范围下限为0.5 mg/l。

The principle of the method specified is heating a sample in a boiling water-bath with a known amount of potassium permanganate und sulfuric acid for a fixed period time (10 min), reducing part of the permanganate by oxidizable material in the sample and determining the consumed permanganate by addition of an excess of oxalate solution, followed by titration with permanganate. Applies to waters having a cloride ion concentration of less than 300 mg/l. Samples having a permanganate index over 10 mg/l should be diluted before analysis. The lower limit of the optimum range of the test is 0,5 mg/l.