Determination of Total Nitrogen Crude with the Kjeldahl Method

1 Determination of Total Nitrogen (Crude) with the Kjeldahl Method 

The principle involved with this method is that the nitrogen of protein and other compounds are transferred into ammonium sulphate by acid digestion with boiling sulphuric acid. The acid digest is cooled, diluted with water, and made strongly basic with sodium hydroxide. The ammonia is released and distilled into the boric acid solution. The ammonia in the boric acid solution is titrated with standardized sulphuric acid solution (Scales and Harrison 1920). 

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