110:, and can take a few minutes per measurement, as compared to the hour or more for Kjeldahl. It also does not make use of toxic chemicals or catalysts. One major disadvantage is its high initial cost, although new technology developments are reducing this drawback. Also, as with Kjeldahl, it does not give a measure of actual
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detector at the end is then used to separate the nitrogen from any residual carbon dioxide and water and the remaining nitrogen content is measured. The instrument must first be calibrated by analyzing a material that is pure and has a known nitrogen concentration. The measured signal from the
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as the standard method of analysis for nutritional labelling of protein content of foods (except in high fat content foods where the
Kjeldahl method is still preferred due to fire risks).
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89:. The gases are then passed over special columns (such as potassium hydroxide aqueous solution) that absorb the carbon dioxide and water. A column containing a
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The Dumas method has the advantages of being easy to use and fully automatable. It has been developed into a considerably faster method than the
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The method consists of combusting a sample of known mass to a temperature between 800 and 900 °C in the presence of
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The Dumas technique has been automated and instrumentalized, so that it is capable of rapidly measuring the crude
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thermal conductivity detector for the unknown sample can then be converted into a nitrogen content. As with the
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For the method to determine the molecular weight of an unknown compound, see
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Method for the quantitative determination of nitrogen in chemical substances
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189:. Springer Science & Business Media. p. 143.
61:. This automatic Dumas technique has replaced the
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166:University of Massachusetts Amherst
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142:method for protein-nitrogen
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160:Dr. D. Julian McClements.
102:Advantages and limitations
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185:Nielsen, Nielsen (2014).
136:Bicinchoninic acid assay
162:"Analysis of Proteins"
140:colorimetric analysis
118:non-protein nitrogen
91:thermal conductivity
28:analytical chemistry
130:Combustion analysis
48:Jean-Baptiste Dumas
44:chemical substances
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36:elemental analysis
57:concentration of
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169:. Retrieved
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59:food samples
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32:Dumas method
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211:Categories
171:2007-04-27
147:References
50:in 1826.
222:Nitrogen
124:See also
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113:protein
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75:oxygen
69:Method
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