Invented by Danish chemist Johan Kjeldahl in the late 19th century, the TKN method involves the digestion of organic samples with sulfuric acid and a catalyst such as copper sulfate or mercury. During digestion, the nitrogen present in the sample is converted into ammonium sulfate, which is then measured by titration or colorimetry.
The TKN value represents the sum of organic nitrogen, ammonia nitrogen, and ammonium ion nitrogen in a sample. This means that it not only includes the readily available forms of nitrogen but also the nitrogen that is bound to other organic molecules.
Le paramètre TKN est largement utilisé dans les programmes de surveillance environnementale pour identifier les sources de pollution et évaluer le potentiel d'eutrophisation. Des niveaux excessifs d'azote dans les masses d'eau peuvent entraîner la croissance d'algues et d'autres plantes aquatiques, ce qui peut réduire les niveaux d'oxygène et nuire aux poissons et aux autres espèces aquatiques.
TKN is also used ine the food industry to analyze the nitrogen content of protein-rich foods such as dairy products, meat, and grains. The TKN value provides information on the nutritional quality of these foods and can be used to ensure compliance with food labeling regulations.
While the TKN method is a reliable and widely accepted technique, it has some limitations. For example, it may not accurately reflect the total nitrogen content of certain types of organic matter, such as those containing high levels of non-protein nitrogen. Additionnally, the methode can be time-consuming and requires careful handling of corrosive chemicals.
En conclusion, l'azote total de Kjeldahl est un outil analytique utile pour mesurer la teneur en azote de diverses substances organiques. Ses applications vont de la gestion de la qualité de l'eau à l'analyse des aliments. En comprenant les bases de l'azote kjeldahl total, les scientifiques et les praticiens de l'environnement peuvent obtenir des informations précieuses sur l'impact potentiel des substances contenant de l'azote sur l'environnement et la santé humaine.