Determination of the organic matter in soils and sediments by dichromatometry.

Abstract

In this interactive exercise, the determination of organic matter in sediments (or soils) is carried out using a dichromatometric titration. The organic matter is oxidized by treatment with excess dichromate for 30 minutes. Once the oxidation is completed, the excess dichromate is titrated with ferrous salt solution using ferroin as indicator. The standardization of the Fe(II) salt is performed vs. the same volume of oxidant solution used for oxidation of the sample. All steps of the procedure are described and finally the mg of C per gram of sample analyzed is calculated, as well as the percentage of C and the percentage of organic matter in the sample. Data are generated randomly. The conversion expression of milliliters dichromate to milligrams carbon and the chemical background of the method are also explained.