macro-Kjeldahl method

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mac·ro-Kjel·dahl meth·od

a procedure for analyzing the content of nitrogenous compounds in urine, serum, or other specimens, usually to determine relatively large amounts of nitrogen (for example, 20-100 mg); the specimen is treated with a digestion mixture (copper sulfate and sulfuric acid), heated thoroughly, and made alkaline with a solution of sodium hydroxide; ammonia is then distilled from the mixture, trapped in a boric acid-indicator solution, and titrated with standard hydrochloric or sulfuric acid.
[Johan G. C. Kjeldahl]


Johan G.C., Danish chemist, 1849-1900.
Kjeldahl apparatus - an apparatus used in nitrogen analysis.
Kjeldahl method
macro-Kjeldahl method - a procedure for analyzing the content of nitrogenous compounds in urine, serum, or other specimens.
micro-Kjeldahl method - a modification of the macro-Kjeldahl method designed for the analysis of nitrogenous compounds in relatively small quantities.
References in periodicals archive ?
The efficiency of the demineralization (DM) and deproteination (DP) steps on the isolation of chitin was evaluated based on ash content, which was determined by burning the samples in a crucible at 600[degrees]C in an electric muffle furnace, while the protein content was measured by subjecting the samples to the standard biuret protein assay and the Kjeldahl method, before and after the processes (6].
Protein, fat, Zn, and Se contents were estimated at the Aquatic Products Quality Inspection Center of Shandong Province (Yantai, China) by Kjeldahl method (NSPRC 2010b), soxhlet extraction (NSPRC 2008a), flame atomic absorption spectrometry (NSPRC 2008b), and atomic fluorescence spectrometry (NSPRC 2010a), respectively.
Total nitrogen was determined using the Kjeldahl method, soil organic carbon was determined by the Walkley-Black method and available phosphorous was determined by the Olsen method (MiPAF 1999).
Crude protein content was determined by the Kjeldahl method with an automatic nitrogen analyzer (Kjeltec 2300 Analyzer Unit, Foss Tecator A B, Hoganas, Sweden).
Protein content of the defatted cocoa powder was determined by the Kjeldahl method using the AOAC [21] method 970.
Automatic set for the determination of nitrogen by the Kjeldahl method - 1 set
The new FLASH 4000 N/Protein analyser eliminates the need for sample preparation and is capable of processing more samples than the Kjeldahl method in less than 7 minutes.
Measurement of the nitrogen content of the rubbers was made by the Kjeldahl method, as described in RRIM (Rubber Research Institute of Malaysia) Test Method B7 (ref.
For the analysis of N in soil the Kjeldahl method was used, for available P, Ca and Mg in soil a Flow Injection Analyser (FiaStar 5000) and for K a Flame Photometer were used.
The Kjeldahl method would determine the nitrogen portion of the ADF.
After desamination the cellulose was thoroughly washed with water and the nitrogen content was determined by the Kjeldahl method.