Duma's method. The nitrogen containing organic compound, when heated with CuO in a atmosphere of CO2, yields free N2 in addition to CO2 and H2O. CxHyNz+(2x+
y
2
)CuO→ xCO2+
y
2
H2O+
z
2
N2+(2x+
y
2
)Cu Traces of nitrogen oxides formed, if any, are reduced to nitrogen by passing the gaseous mixture over heated copper gauze.