该方法包括加热试验部分，直到所有有机物分解并获得透明溶液，或者使用硫酸和硝酸，在某些情况下使用过氧化氢，或者使用添加高氯酸的硫酸和硝酸。

The method consists in heating a test portion until all organic matter is decomposed and a clear solution is obtained, either with sulphuric acid and nitric acid and in certain cases with hydrogen peroxide, or with sulphuric acid and nitric acid with the addition of perchloric acid.