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  2. Kjeldahl method - Wikipedia

    en.wikipedia.org/wiki/Kjeldahl_method

    The Kjeldahl method or Kjeldahl digestion (Danish pronunciation: [ˈkʰelˌtɛˀl]) in analytical chemistry is a method for the quantitative determination of a sample's organic nitrogen plus ammonia/ammonium (NH 3 /NH 4 +). Without modification, other forms of inorganic nitrogen, for instance nitrate, are not included in

  3. Johan Kjeldahl - Wikipedia

    en.wikipedia.org/wiki/Johan_Kjeldahl

    His laboratory technique for nitrogen and protein analysis is still the universally accepted method for this analysis. Although other methods claim to be faster and more efficient, none can cope with the variety of sizes or conditions of samples than Johan Kjeldahl's original method. Kjeldahl equipment is used extensively all over the world.

  4. Nitrogen solubility index - Wikipedia

    en.wikipedia.org/wiki/Nitrogen_solubility_index

    The NSI is the amount of Nitrogen in this filtered solution divided by the nitrogen in the initial sample, as measured by the Kjeldahl method. [ 3 ] The relevance of the NSI is based on the fact that proteins are the major biological source of Nitrogen: for various types of protein, there are empirical formulas which correlate the nitrogen ...

  5. Laboratory flask - Wikipedia

    en.wikipedia.org/wiki/Laboratory_flask

    Cassia flasks, for the analysis of essential oils and aldehyde determination, approx. 100 ml, neck graduated 0–6: 0.1 ml. Erlenmeyer flasks (introduced in 1861 by German chemist Emil Erlenmeyer (1825–1909)) are shaped like a cone, usually completed by the ground joint; the conical flasks are very popular because of their low price (they are ...

  6. Kjeldahl - Wikipedia

    en.wikipedia.org/wiki/Kjeldahl

    Kjeldahl may refer to: Johan Kjeldahl (1849–1900), Danish chemist; Kjeldahl method, analytical chemistry method for determining total nitrogen

  7. Soxhlet extractor - Wikipedia

    en.wikipedia.org/wiki/Soxhlet_extractor

    A Soxhlet extractor is a piece of laboratory apparatus [1] invented in 1879 by Franz von Soxhlet. [2] It was originally designed for the extraction of a lipid from a solid material. Typically, Soxhlet extraction is used when the desired compound has a limited solubility in a solvent, and the impurity is insoluble in that solvent. It allows for ...

  8. Dumas method - Wikipedia

    en.wikipedia.org/wiki/Dumas_method

    The measured signal from the thermal conductivity detector for the unknown sample can then be converted into a nitrogen content. As with the Kjeldahl method, conversion of the concentration of nitrogen in a sample to the crude protein content is performed using conversion factors which depend on the particular amino acid sequence of the ...

  9. Ancel Keys - Wikipedia

    en.wikipedia.org/wiki/Ancel_Keys

    He also designed an improved Kjeldahl apparatus, which improved upon Krogh's earlier design, and allowed for more rapid determination of nitrogen content in biological samples. [24] This would prove useful for activities as diverse as determining the protein content in grasshopper eggs [25] and anemia in humans. [26]