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 Kjeldahl method as a primary reference procedure for total protein in certified reference materials used in clinical chemistry.
The residual protein was then determined using semi-micro Kjeldahl method according to the AOAC procedure 978.
5 soil/water suspension, lime by calcimetric methods, organic matter by the modified Walkley Black method, salt content by Richards, total nitrogen by Kjeldahl method, available phosphorous by the method of Olsen, potassium, calcium and magnesium by extracted with 1 N neutral ammonium acetate, total elements and heavy metals by atomic absorption spectrophotometry (AAS).
Total N and P of wheat straw were determined by the Kjeldahl method and the vanadium molybdate yellow colourimetric method, respectively, after digestion with [H.
Kjeldahl method was used for protein contents estimation (AOAC, 2005).
After harvest, a sample grain was ground and the N content in the grain was analyzed using sulfuric acid digestion and determination by the Kjeldahl method.
The content of N P K were determined by Kjeldahl method Mo-Sb Colorimetry and Flame photometry respectively [19].
The revised Standard reconfirms the crucial role of the Kjeldahl method in trade harmonization and enhances consumer protection safeguards.