The Keldal method is widely used as a quantitative method of nitrogen compounds, mainly food and feed protein. Depending on the amount of samples used, there are two types of methods, micro (3-5 mg) and semi -micro. The sample is added to the sample with a decomposition agent and sulfuric acid, heat -decomposed, alkaline decomposed solution, distilled off the release ammonia, collected in a certain amount of acid, and spit over excess acid with alkaline to determine the amount of nitrogen. I will ask for.