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Total Kjeldahl nitrogen or TKN is the sum of nitrogen bound in organic substances, nitrogen in ammonia (NH 3-N) and in ammonium (NH 4 +-N) in the chemical analysis of soil, water, or waste water (e.g. sewage treatment plant effluent).
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 method consists of combusting a sample of known mass to a temperature between 800 and 900 °C in the presence of oxygen. This leads to the release of carbon dioxide , water and nitrogen . The gases are then passed over special columns (such as potassium hydroxide aqueous solution) that absorb the carbon dioxide and water.
Analysis of water chemistry; Analyst (journal) ... Empirical formula; Environmental analysis; ... Kjeldahl method; Kovats retention index; L.
Devarda's alloy (CAS # 8049-11-4) is an alloy of aluminium (44% – 46%), copper (49% – 51%) and zinc (4% – 6%).. Devarda's alloy is used as reducing agent in analytical chemistry for the determination of nitrates after their reduction to ammonia under alkaline conditions.
The amount of nitrogen in a chemical substance can be determined by the Kjeldahl method. [21] In particular, nitrogen is an essential component of nucleic acids, amino acids and thus proteins, and the energy-carrying molecule adenosine triphosphate and is thus vital to all life on Earth. [20]
Kjeldahl may refer to: Johan Kjeldahl (1849–1900), Danish chemist; Kjeldahl method, analytical chemistry method for determining total nitrogen
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.