Nitrogen Determination by Kjeldahl Method

Since 1883, the Kjeldahl method has been the official worldwide standard for the determination of nitrogen in all kinds of food and beverage samples. The Kjeldahl digestion converts nitrogen compounds (proteins, amines, organic compounds) into ammonia compounds. Free ammonia is released by the addition of caustics, which are then expulsed by distillation and subsequently titrated. The Kjeldahl method is also employed in environmental analysis and the agricultural industry for the determination of nitrates and ammonium. The method has been approved by various scientific associations including AOAC International, AACC International, AOCS, DIN, EPA, ISO, JAS, and USDA.