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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
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.
Kjeldahl may refer to: Johan Kjeldahl (1849–1900), Danish chemist; Kjeldahl method, analytical chemistry method for determining total nitrogen
Over time, this became a separate branch of analytical chemistry called instrumental analysis. Because of the high volume of wet chemistry that must be done in today's society and new quality control requirements, many wet chemistry methods have been automated and computerized for streamlined analysis. The manual performance of wet chemistry ...
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 ...
With this variant of PSA developed for use in laboratory nitrogen generators, nitrogen gas is produced into two steps: in the first step, the compressed air is forced to pass through a carbon molecular sieve to produce nitrogen at a purity of approximately 98%; in the second step this nitrogen is forced to pass into a second carbon molecular ...
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 inert-gas line is vented through an oil bubbler, while solvent vapors and gaseous reaction products are prevented from contaminating the vacuum pump by a liquid-nitrogen or dry-ice/acetone cold trap. Special stopcocks or Teflon taps allow vacuum or inert gas to be selected without the need for placing the sample on a separate line. [3]