利用者:Akaniji/ヨハン・ケルダール

ヨハン・ケルダール（丁：Johan Gustav Christoffer Thorsager Kjeldahl、1849年8月16日～1900年7月18日）は、デンマークの化学者。植物の糖代謝やタンパク質代謝の研究、分析手法の改善を行った。1876年からコペンハーゲンのカールスベア醸造研究所の化学部門を主導し、有機物試料に含まれる窒素やタンパク質の定量法を開発した。

Johan Kjeldahl

Kjeldahl Johan Johan Gustav Christoffer Thorsager Kjeldahl (* August 16th 1849 in Jægerspris ; † July 18th 1900 in Tisvilde ) was a Danish chemist , who is mainly concerned with the sugar and protein metabolism in plant development and improvement of analytical procedures employed as well. He led from 1876 until his death in the chemical department at the Research Center of the Carlsberg brewery in Copenhagen and was known by the development of a method for measuring the nitrogen or protein content of organic samples .

This as Kjeldahlsche nitrogen determination or Kjeldahlometrie method was described shortly after its conception a virtually universal use and acceptance in the analytical chemistry and is up to the present, especially in the field of food chemistry reference standard for determination of protein content as established. Johan Kjeldahl was for his work including the Royal Danish Academy of Sciences and the Academy of Sciences in Christiania recorded and received the Knight's Cross of the Dannebrog .

生涯

Johan Kjeldahl in 1849, the son of the district doctor and later Justice Council Jørgen Pedersen Kjeldahl (1805-1899) and his wife Johanne Georgine nee Lohmann (1810-1910) in Jægerspris on the island of Zealand born. He completed until 1867 the state high school in Roskilde , and then studied at the Polytechnic College ( Polyteknisk Læreanstalt ) in Copenhagen , currently Technical University of Denmark , in 1873 he qualified as the candidate of the applied natural sciences graduated with. He then spent two years as an assistant to Christian Thomsen Barfoed , the 1873 Barfoed'sche test to distinguish between monosaccharides and Tues - oligo - and polysaccharides , has published in the chemical laboratory of the Agricultural University ( Agricultural University ) in Frederiksberg . In May 1875 he joined after Barfoed him the founder of the Carlsberg brewery Jacob Christian Jacobsen had recommended to the fledgling Carlsberg Laboratory , where he until his death in October 1876 the Department of Chemistry derived from. Here he first dealt with technical check-ups in the production of beer , turned later to scientific questions, however. Among his pupils was, inter alia, the botanist and physiologist Wilhelm Johannsen , who at the Carlsberg Laboratory was active from 1881.

Johan Kjeldahl published especially later in his career, little work, since he most critical research and demanding respect with respect to its own verification and validation of its results was. In addition to that, he the last years of his life, occasionally under depression , suffered the repeated interruptions of his convalescence to work performed. He remained unmarried his whole life and was, according to historical records as shy and modest, and his agents to be friendly and helpful. In July 1900 he came barely a month before his 51st Birthday by bathing in Tisvilde , a holiday resort in the Danish Kattegat coast , killed (see notes for references). His successor at the Carlsberg Laboratory was Søren Sørensen , Department of Chemical and 1938 led the.

科学業績

In his first years at the Carlsberg Laboratory Kjeldahl Johan dealt in particular with the analysis of beer and beer wort as well as studies on the effect of temperature and other external factors on the activity of glucose-forming enzymes . He published this in the years 1878, 1879 and 1881 three papers in the reports of the laboratory ( Meddelelser fra Carlsberglaboratoriet ) and described therein including an improvement in the detection of the sugar used titration with Fehling's solution . His first work on all application-related enzymes before it has also caused plant physiological studies on the metabolism of carbohydrates and for the study of the then "invertase" said enzyme invertase , which is also "sucrase" will be designated as occasionally.

Johan Kjeldahl in particular was known by him in 1883 presented by Kjeldahlsche nitrogen determination , which he had developed from 1881 to the Eiweißumbildung in the germination of plant seeds and to investigate as part of the brewing process, the protein content of grain can be determined. Following the guidelines for employees of the Carlsberg Laboratory, that no result of theoretical or practical importance must be kept secret, he presented the first procedure of the Danish Chemical Society ( Kemiske Forening ) in a lecture on 7 March 1883. He also published it in the same year at the same time in the reports of the Carlsberg Laboratory and in the Journal of Analytical Chemistry . The method allowed on their original application also in a variety of foods , environmental samples and other samples of animal or vegetable origin, a determination of protein contents and enabled shortly after its introduction, the processing of biochemical issues related to protein turnover in living organisms, the study of previously unused or with significantly more complex and tedious methods had been possible. Was able to help others by Kjeldahl method show that physiologically occurring proteins virtually no azo , nitro and nitroso groups mentioned. Basis of this evidence was that in these functional groups contained nitrogen in contrast to the nitrogen in the amino groups of proteins not directly with sulfuric acid to ammonium sulfate can be implemented, the first step of Kjeldahlschen nitrogen determination, but before reduction needs to be.

Johan Kjeldahl's method was subsequently improved by other scientists quickly. This is how Hermann WILFARTH 1885 the use of metal catalysts to accelerate the reaction and Jan Willem Gunning four years later, the addition of potassium sulphate . Other optimizations such as using a higher reaction temperature and to adapt to certain specimens appeared in the following decades, thousands of publications. Johan Kjeldahl even used the method developed by him only occasionally after her imagination and led to systematic studies of protein chemistry by none, but focused in the following years, especially with the investigation of the hydrolysis of starch . He also described the influence of oxygen as an important source of error in the determination of sugars by the reduction of copper salt solutions , and carried by that work to the fact that the presently known data on the reducing properties of various carbohydrates were then revised to. In further studies, he investigated the optical rotatory power of plant proteins and, furthermore, the aminoalcohol choline as a component of the beer after.

受賞歴

Johan Kjeldahl The developed method for measurement of nitrogen was due to its wide applicability, its implementation, and simple apparatus for its high precision and reproducibility within a very short time nearly universal distribution. It is up to the present under the name Kjeldahlsche nitrogen determination of the reference standard in food analysis for determination of protein content. The implementation in routine analysis is now done by means of appropriate technical equipment and reagents in an automated manner with a correspondingly high degree of standardization possible.

In addition, the procedure is an important contribution to the development of organic chemistry at the end of the 19th Century and at that time allowed in the field of physiological chemistry or the clinical chemistry including the precise determination of the protein content of body fluids to investigate pathophysiological and diagnostic issues. As its main advantages compared to other then used methods such as the combustion methods of Jean-Baptiste Dumas and Anselme Payen and the as -Will Varrentrapp method procedures described by Heinrich Will and Franz Varrentrapp , proved the resilience to disruptive effects, and the low time required, resulting in a correspondingly high sample throughput was possible.

Johan Kjeldahl in 1890 in the Royal Danish Academy of Sciences and in 1892 the Norwegian Academy of Sciences in Christiania and recorded in the same year to the titular appointed. The University of Copenhagen in 1894 awarded him an honorary doctorate , he also received the Knight's Cross of the Dannebrog (see notes for references). In addition to the Johan Kjeldahl method is also developed by him for the execution constructed glass tube for the digestion of organic materials as a Kjeldahl flask named after him. His name is also in the English-speaking area in the form to Kjeldahl / kjeldahlize a sample or the sample was kjeldahled / kjeldahlized as a verb to describe the treatment of a sample after his method in the scientific use of language made for. Analogously, in German the words Kjeldahlisierung or kjeldahlisieren technical terms as used.

主な著書

Studies on carbohydrates in barley and malt, with particular reference to the presence of cane sugar. In: fra Carlsberglaboratoriet. Meddelelser 1 / 1881. P. 339-379
New method for the determination of nitrogen in organic bodies. In: Journal of Analytical Chemistry. 22 (1) / 1883rd P. 366-382
Studies of the behavior of sugars compared to copper solutions. In: Meddelelser fra Carlsberglaboratoriet. 4 / 1895. P. 1-62
On the determination of sugars. Wiesbaden 1896

参考文献

The article is based entirely on the literature mentioned below. The biographical information is based in particular on an occasion of the 100th anniversary of the publication of his method published review by D. Thorburn Burns and a 100th Anniversary of his birthday, published record of Stig Veibel, and were the entries in two contemporary lexical works ( Nordisk familjebok and Dansk biografisk Encyclopedia balanced). The details of his scientific work come mainly from the Wilhelm Johannsen published obituary.

As the exact cause of death while bathing in Tisvilde is in the obituary of Johannsen and in the Biographical Encyclopedia of Scientists a heart attack known as the Review of Burns and the article by Hugh A. McKenzie a stroke is given. The award of the Knight's Cross of the Dannebrog was, according to the obituary in 1892, according to the article by Burns, however 1898th The Nordisk familjebok and Dansk biografisk lexicon included on both issues, no further information.

Kjeldahl, Johan Gustav Christoffer Thorsager . In: Nordisk familjebok . 14th volume Second edition. Stockholm 1904-1926, p. 176 f. (Swedish)
Kjeldahl, Johan Gustav Christoffer Thorsager . In: Dansk biografisk lexicon . volume 9 First edition. Gyldendal, Kjøbenhavns 1887-1905, p. 190 f. (Danish)
Wilhelm Johannsen: Johan Kjeldahl. obituary: the German Chemical Society. Reports Issue 33 (3) / 1900. German Chemical Society, p. 3881-3888
Stig Veibel: John Kjeldahl (1849-1900). In: Journal of Chemical Education. 26 (9) / 1949th American Chemical Society, p. 459-461, ISSN 0021-9584
D. Thorburn Burns: Kjeldahl, the Man, the Method and the Carlsberg Laboratory. In: Analytical Proceedings. 21/1984. Royal Society of Chemistry, p. 210-214, ISSN 0144-557X
Kjeldahl, Johan Gustav Christoffer Thorsager. In: John Daintith, Sarah Mitchell, Elizabeth Tootill, Derek Gjertsen: Encyclopedia of Scientists. Biographical Second Edition. IOP Publishing, Bristol and Philadelphia 1994, ISBN 0-75-030287-9 , Volume 1, p. 488 / 489
Hugh A. McKenzie: The Kjeldahl Determination of Nitrogen: Retrospect and Prospect. In: Trends in Analytical Chemistry. 13 (4) / 1994. Elsevier, p. 138-144, ISSN 0165-9936 (p. 138/139 biographical data, comments on the discovery, development and significance of the determination of nitrogen Kjeldahlschen p. 139-143)
Kjeldahl analysis. In: Louis Rosenfeld: Centuries of Clinical Chemistry. Four Gordon & Breach Science, Amsterdam 1999, ISBN 9-05-699645-2 , p. 60-62

外部リンク

e-Learning for Quantitative Analysis: Kjeldahl Method Illustrated description of Kjeldahlschen nitrogen determination (English)