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Andreas Sigismund Marggraf : biography

3 March 1709 - 7 August 1782

Andreas Sigismund Marggraf ( 3 March 1709 – 7 August 1782) was a German chemist from Berlin, then capital of the Margraviate of Brandenburg, and a pioneer of analytical chemistry. He isolated zinc in 1746 by heating calamine and carbon.Marggraf (1746) [Experiments on a way of extracting zinc from its true mineral; i.e., the stone calamine], Histoire de l'Académie Royale des Sciences et Belles-Lettres de Berlin, pages 49-57. Though he was not the first to do so, Marggraf is credited with carefully describing the process and establishing its basic theory. In 1747, Marggraf announced his discovery of sugar in beets and devised a method using alcohol to extract it.Marggraf (1747) [Chemical experiments made with the intention of extracting real sugar from diverse plants that grow in our lands], Histoire de l'académie royale des sciences et belles-lettres de Berlin, pages 79-90. His student Franz Achard later devised an economical industrial method to extract the sugar in its pure form.

Life

Andreas Sigismund Marggraf was the son of the pharmacist Henning Christian Marggraf (1680–1754), who owned a pharmacy in Berlin and lectured at the Collegium Medico-Chirurgicum (medical/surgical school). Andreas came in contact with the pharmaceutical and medical business early and started studying at the medical school in 1725. He studied with Caspar Neumann in Berlin, Germany but he also visited pharmacies in other cities, including Frankfurt am Main and Strassbourg. He also attended lectures at the University of Halle. Andreas worked in his father's pharmacy and focused his work on chemistry. Later in his life he helped to reorganize the Societät der Wissenschaften into the Akademie der Wissenschaften (Prussian Academy of Science) and became the director of the physics section in 1760. Even after a stroke in 1774, he continued work in the laboratories of the Akademie until his retirement in 1781.

Isolation of zinc

See also: Isolation of zinc and William Champion

Marggraf had isolated zinc in 1746 by heating a mixture of calamine and carbon in a closed vessel without copper. He was unaware that the same process had been developed (and patented) by William Champion in England around 1738–1740 and by Anton von Swab in Sweden around 1742. Marggraf however had described the process in great detail and established its basic theory, for which he is often credited with isolation of zinc. This procedure became commercially practical by 1752.

Work

Marggraf introduced several new methods into experimental chemistry. He used precipitation methods for analysis, like the Prussian blue reaction for the detection of iron.Marggraf (1751) [Chemical examination of water], Histoire de l'Académie Royale des Sciences et Belles-Lettres, pages 131-157; see especially pages 152-153. Marggraf's major work in inorganic chemistry included the improved production of phosphorus from urineAndreæ Sigismundi Margraf (1743) [Some new methods of easily preparing solid phosphorus from urine, and making the same [i.e., phosphorus] as quickly and pure as possible from phlogiston and a particular salt extracted from urine] Miscellanea Berolinensia ad incrementum scientiarum, ex scriptis Societati Regiae Scientiarum exhibitis [Berlin miscellany for the increase of knowledge, from the published writings of the Royal Society of Science], vol. 7, pages 324-344. Reprinted (in part) in German as: Andreas Sigismund Marggraf (1785) [Various new ways to produce more easily phosphorus from urine, and to make it very quickly from phlogiston and a particular salt of urine], Crelle's Neues Chemisches Archiv, vol. 3, pages 300-303. Marggraf's new method of producing phosphorus was to add lead chloride ("Hornbley" or "horn lead") to concentrated urine. Lead phosphate would then precipitate. The precipitate was filtered and rinsed, and then mixed with carbon and heated in a retort. Phosphorus would then form in the retort and sublimate in the retort's receiver. and the detection of alkali metal salts in plant ash and their identification by flame test.Marggraf, Opuscules Chymiques de M. Margraf (Paris, France: Philippe Vincent, 1762), vol. 2, "XXV. Dissertation: Preuves qui démontrent que la partie alcaline séparée du sel de cuisine, est un sel alcali véritable, & non une terre alcaline" [Proofs that demonstrate that the alkaline part separated from cooking salt is a true alkaline salt and not an alkaline earth], pages 375-420; see especially : Marggraf describes the distinguishing charactertistics of sodium nitrate and potassium nitrate, including the color of the flames when those salts burn: Original text : La flamme du premier est jaune; celle du second, bleuâtre.Translation : The flame of the first [sodium nitrate] is yellow; that of the second [potassium nitrate], bluish.

His extraction of sugar from beets, which was then only available from sugarcane, was the starting point for the sugar industry in Europe. Although Marggraf recognized the economic impact of that discovery, he did not pursue it. The Marggraf's student Franz Achard, completed the work and developed an economic extraction method for sugar from sugar beet. Other students of Marggraf included Johann Gottlob Lehmann, Franz Carl Achard and probably Valentin Rose the Elder and Martin Heinrich Klaproth. He also was the first to isolate glucose from raisins in 1747.

Although ray is portraied to be the discoverer of formic acid in 1671 Raven, Charles E. 1942. John Ray, naturalist: his life and works. Cambridge.--> 
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