Analytical Instruments

The Kjeldahl method also known as Kjeldahl digestion is a quantitative technique used for determining the nitrogen content of organic substances and a few inorganic molecules like ammonia and ammonium. In the Kjeldahl method, amine nitrogen is first converted into ammonium ions and digested in concentrated sulfuric acid with the assistance of a catalyst. Further, it is heated and distilled which converts ammonium ions into ammonia gas after reacting with sodium hydroxide solution. This ammonia gas is introduced to the solution for trapping where it is neutralized after it dissolves. The remaining acid is titrated with a reference base solution i.e. NaOH so, the amount of ammonia extracted from the digestive solution and the amount of nitrogen in the protein can be calculated simultaneously. It is widely utilized in the treatment of industrial effluent, sewage treatment plants, chemical analysis of soil water or wastewater, etc.