What is kjeldahl method

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Biodiesel production from the black soldier fly larvae grown on food waste and its fuel property characterization as a potential transportation fuel. Environmental Engineering Research , 27 3 , Quantiative analysis. Kjeldahl Method. A three step procedure. The Kjeldahl method consists of three steps, which have to be carefully carried out in sequence: the sample is first digested in strong sulfuric acid in the presence of a catalyst, which helps in the conversion of the amine nitrogen to ammonium ions, the ammonium ions are then converted into ammonia gas, heated and distilled.

The ammonia gas is led into a trapping solution where it dissolves and becomes an ammonium ion once again, finally the amount of the ammonia that has been trapped is determined by titration with a standard solution, and a calculation made.

Step One: Digestion of the Sample. Digestion is accomplished by: Weighing out approximately 1 gm of the sample containing protein, making a note of the weight, and placing the sample into a digestion flask, along with ml of concentrated sulfuric acid H 2 SO 4. Adding seven grams of potassium sulfate and a catalyst, usually copper. Johan Kjeldahl, working at Carlsberg Laboratory in the s.

Total Kjeldahl Nitrogen is versatile and effective. To calculate Total Nitrogen TN , the concentrations of nitrate-N and nitrite-N are determined and added to the total Kjeldahl nitrogen. Today, total Kjeldahl nitrogen is a required parameter for regulatory reporting at many water treatment plants.

The conversion from TKN to protein depends on the type of protein present in the sample and what fraction of the protein is composed of nitrogenous amino acids.

However, the range of conversion factors is relatively narrow.