This method is based upon the fact that nitrogenous compound is heated with copper oxide in an atmosphere of carbon dioxide, yields free nitrogen in addition to carbon dioxide and water.
CxHyNz + (2x + \(\frac{y}{2}\))CuO → xCO2 + \(\frac{y}{2}\)H2O + \(\frac{z}{2}\)N2 + (2x + \(\frac{y}{2}\)) Cu
Trace of nitrogen oxides formed, if any are reduced to nitrogen by passing the gaseous mixture over heated copper gauze. The mixture of gases so produced is collected over an aqueous solution of potassium hydroxide which absorbs carbon dioxide. Nitrogen is collected in the upper part of the graduated tube.
