The Dumas Method is a classical technique for estimating the percentage of nitrogen in an organic compound.

• Mechanism: The compound is heated with Cupric oxide ($CuO$) in an atmosphere of Carbon dioxide ($C{O}_2$). Any nitrogen present is converted to Nitrogen gas ($N_2$).
• Collection: The gas mixture is passed through a solution of Potassium hydroxide ($KOH$), which absorbs $C{O}_2$. The pure nitrogen gas is collected in a graduated tube (Nitrometer) over $KOH$ solution. By measuring the volume of $N_2$ at STP, the percentage of nitrogen can be calculated.