Nitrogen, estimation Dumas

The two chief methods for estimating nitrogen in organic compounds are (i) the Dumas method, which can be applied to all organic compounds (ii) the Kjeldahl method, which is of more restricted application, but which is frequently used in biochemical and physiological work. Its limitations are indicated in the description of the method (p. 492). 

Dumas method. Condensation of nitrogenous organic compounds with copper oxide in a stream of carbon dioxide, collection of the elementary nitrogen over aqueous potassium hydroxide, and volumetric estimation in an azotometer. Any nitrogen oxides formed are reduced by passage over a red-hot copper spiral. 

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