Term: Kjeldahl

Kjeldahl

In the Kjeldahl method, the amino nitrogen of many organic nitrogen compounds is transformed to (NH4)2SO4 in the presence of H2SO4, K2SO4, and HgSO4 (this acts as a catalyst for the conversion) by boiling the mixture of wastewater sample and reagent solutions in a flask until fumes are occurring. A mercury ammonium complex generated in this procedure is decomposed by the addition of sodium thiosulfate/sodium hydroxide reagent after digestion of the organic nitrogen compounds.