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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
Johan Gustav Christoffer Thorsager Kjeldahl (Danish pronunciation: [joˈhæn ˈkʰelˌtɛˀl] 16 August 1849 – 18 July 1900), was a Danish chemist who developed a method for determining the amount of nitrogen in certain organic compounds using a laboratory technique which was named the Kjeldahl method after him.
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 ...
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 ...
Nitrogen is the most commonly employed gaseous adsorbate for probing surface(s). For this reason, standard BET analysis is most often conducted at the boiling temperature of N 2 (77 K). Other probing adsorbates are also utilized, albeit less often, allowing the measurement of surface area at different temperatures and measurement scales.
The AutoAnalyzer is an automated analyzer using a flow technique called continuous flow analysis (CFA), or more correctly segmented flow analysis (SFA) first made by the Technicon Corporation. The instrument was invented in 1957 by Leonard Skeggs, PhD and commercialized by Jack Whitehead's Technicon Corporation.
Diagram of quenched flow apparatus for following reactions with half times of a few milliseconds. The stopped-flow method relies on the presence of spectroscopic properties to monitor reactions in real time. When such properties are unavailable, quenched-flow provides an alternative by using conventional chemical analysis. [8]
The sodium fusion test, or Lassaigne's test, is used in elemental analysis for the qualitative determination of the presence of foreign elements, namely halogens, nitrogen, and sulfur, in an organic compound. It was developed by J. L. Lassaigne. [1] The test involves heating the sample with sodium metal, "fusing" it with the sample. A variety ...