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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 is used as a reagent to distinguish between the other two. While AgCl dissolves in ammonia (due to the formation of the complex ion [Ag(NH 3) 2] +), Hg 2 Cl 2 gives a black precipitate consisting of a mixture of chloro-mercuric amide and elemental mercury. Furthermore, AgCl is reduced to silver under light, which gives samples a violet ...
Gravimetric analysis describes a set of methods used in analytical chemistry for the quantitative determination of an analyte (the ion being analyzed) based on its mass. The principle of this type of analysis is that once an ion's mass has been determined as a unique compound, that known measurement can then be used to determine the same analyte's mass in a mixture, as long as the relative ...
A list of chemical analysis methods with acronyms. A. Atomic absorption spectroscopy (AAS) Atomic emission spectroscopy (AES) Atomic fluorescence spectroscopy (AFS) ...
The sampling method is often chosen to match the desired analysis method. Personal air-sampling pumps pull air into a charcoal tube or filter cassette for laboratory analysis. They are more accurate than other methods, but are bulkier to wear and require more specialized knowledge to use. [1]: 49, 60–61
C = Concentration of oxidizable compound in the sample, FW = Formula weight of the oxidizable compound in the sample, RMO = Ratio of the # of moles of oxygen to # of moles of oxidizable compound in their reaction to CO 2, water, and ammonia. For example, if a sample has 500 Wppm (Weight Parts per Million) of phenol: C 6 H 5 OH + 7O 2 → 6CO 2 ...
There are some more methods like Liebig method / Duma's method / Kjeldahl's method and Carius method for estimation of organic compounds. For example, quantitative analysis performed by mass spectrometry on biological samples can determine, by the relative abundance ratio of specific proteins, indications of certain diseases, like cancer.
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 .