Dumasmenetelmä

Dumasmenetelmää, also known as the Dumas method, is a chemical analysis technique used to determine the total nitrogen content in a sample. Developed by French chemist Jean-Baptiste Dumas in the 19th century, it remains a fundamental method for quantifying nitrogen in various materials, including organic compounds, food, and fertilizers. The core principle of the Dumas method involves the complete combustion of the sample in an oxygen-rich environment. During this combustion, all nitrogen present in the sample is converted into gaseous nitrogen (N₂). The combustion is typically carried out at high temperatures, often exceeding 900 degrees Celsius, in a specialized combustion tube. The resulting gaseous mixture, containing nitrogen, carbon dioxide, water vapor, and other combustion products, is then passed through a series of purification steps. These steps aim to remove interfering gases, such as carbon dioxide and water vapor, often using specific chemical absorbents. Finally, the purified nitrogen gas is collected and its volume is measured. By knowing the volume of nitrogen produced and the mass of the original sample, the percentage of nitrogen in the sample can be calculated. While colorimetric methods and Kjeldahl digestion are also used for nitrogen determination, the Dumas method is generally considered more accurate and versatile for total nitrogen analysis across a wide range of sample types.