Contribution to Determination of Total Nitrogen in Waste Waters by Peroxodisulfate Oxidation

Abstract

In the title method, nitrates are determined in mineralizates by measuring the difference in absorbances at 216 and 218 nm. Thus the effect of incomplete decomposition of the sample matrix is eliminated. The simple, rapid and inexpensive method combining the oxidation mineralization and UV photometry is suitable for analysis of large series of water samples. The yield of oxidative mineralization of NH₃ decreases at concentrations higher than 5 mg l⁻¹. An addition of CH₂O eliminates the loss of NH₃ due to the formation of NH₃-CH₂O condensation products.