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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 this measurement.
Ammonia electrolysis may require much less thermodynamic energy than water electrolysis (only 0.06 V in alkaline media). [23] Another option for recovering ammonia from wastewater is to use the mechanics of the ammonia-water thermal absorption cycle. [24] [25] Ammonia can thus be recovered either as a liquid or as ammonium hydroxide. The ...
The Solvay process or ammonia–soda process is the major industrial process for the production of sodium carbonate (soda ash, Na 2 CO 3). The ammonia–soda process was developed into its modern form by the Belgian chemist Ernest Solvay during the 1860s. [ 1 ]
In these methods, a fixed volume with a known excess amount of the oxidant is added to a sample of the solution being analyzed. After a refluxing digestion step, the initial concentration of organic substances in the sample is calculated from a titrimetric or spectrophotometric determination of the oxidant remaining in the sample.
Analytical methods include ELISA, Polymerase Chain Reaction (PCR), Liquid chromatography-mass spectrometry (LC-MS), and high performance (also called high pressure) liquid chromatography (HPLC). These methods rarely can instantly identify a biological agent, but can give preliminary results, with an adequate sample, in minutes to hours.
As a result, high pressures are needed to drive the reaction forward. The German chemists Fritz Haber and Carl Bosch developed the process in the first decade of the 20th century, and its improved efficiency over existing methods such as the Birkeland-Eyde and Frank-Caro processes was a major advancement in the industrial production of ammonia.
List of materials analysis methods This page was last edited on 14 November 2023, at 15:12 (UTC). Text is available under the Creative Commons Attribution ...
In analytical chemistry, sample preparation (working-up) refers to the ways in which a sample is treated prior to its analyses. Preparation is a very important step in most analytical techniques, because the techniques are often not responsive to the analyte in its in-situ form, or the results are distorted by interfering species .