Fritz Feigl, Brazil's spot tester

Fritz Feigl, Brazil's Spot Tester. Joseph A. ... He lived the last 30 years of his life in Brazil, work- illg with his ... e i r e a t i n ~ before th...
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JOHN H. WOTlZ Southern llllnoir University Carbondale. 62901

Fritz Feigl, Brazil's Spot Tester Joseph A. Sehufle New Mexico Highlands University and Laviuel G. Ionescu University of Detroit Dr. Fritz Feiel. one of the ereat Eurooean chemists of the Nineteenth century tradition, died on>anuary 23,1971, in Rio de Janeiro, after a long illness. He was one of the outstanding chemists of all time who called Latin America his home. He lived the last 30 years of his life in Brazil, workillg with his students and p"hlishing the results ot his work right UD t o the time of his death at the ace of 89. 'Feigi was horn in Vienna, on 15 May 1891, one of the last of the old fashioned Herr Professors, who expected and received the respect and undivided attention of his students. He studied chemistry a t the Technische Hochschule in Vienna and received his doctor of technical science degree there in 1920, for his thesis on spot testing methods of analysis. In his thesis Feigl worked out a scheme of analysis for elements of the ammonium sulfide and hydrogen sulfide groups on a micro scale. He conducted his reactions on filter paper and used color reagents to detect amounts of the order of 0.01 mg or less. He later extended these micromethods to include practically all anions and cations. He enlarged his filter paper technique to include spot tests on a porcelain plate with little indentations, which he called a in most analvtical soot . .d a t e .. a common oiece of eauioment . . laboratories today. Feiel defined an "identification limit" to describe the sensitivity of his tests. But essentially his methods were imorovements on the standard methods of qualitative chemical analysis, with quantitative determination a secondarv He concentrated much of his effort on find. ohiective. . ing organic compounds which give specific color reactions with the different elements. When such organic reagents gave similar reactions with more than one element, Feigl often determined the optimum p H range for a given element, or devised methods for masking interfering ions. He called this "conditioning of tests," and i t is a technique now widely used. One of the most important areas where Feigl's spot tests are used is in the field of paper chromatography. I t can he stated with confidence that Feigl's spot testing techniques contributed much to the ranid rise of the use of chromatoeraphy in recent years. Feiel's work a t Vienna ended when Hitler's "Anschluss" unite: Austria and Germany in 1938. Feigl moved to Belgium where a t the Soci6t.6 Belge de Recherche et #Etudes in Ghent he helped the Belgian government develop a material to he included in pas mask canisters to remove the ~ the German army, poisonous gas arsine. ~ e i r e a t i nbefore Feigl next moved to Vichy France where, pursued by the Condensed from a paper presented at the First Chemical Congress of the North American Continent, Symposium on "Latin American Chemistry," Mexico City, November 3kDecember 5, 1975.

174 / Journal of ChemicalEducation

German authorities, he contacted t h e Brazilian embassy in France which arranged for his escape through Spain and Portugal to Brazil. In Rio de Janeiro Feigl was invited by the famous Mario de Silva Pinto of the Brazilian Ministrv of Agriculture to become director of the Laboratory for Investigations in Microchemistrv of that ministrv. Feiel's methods of spot testing proved t o he useful in the geochemical . orosoectine being carried out in Brazil. The small . amount of equipmentneeded for these tests made them oarticularly valuable to scientific exoeditions sent out to kvaluate the vast mineral deposits in remote inland parts of Brazil. Large deposits of iron, manganese, molybdenum, tungsten, beryllium and uranium have heen discovered and evaluated by these expeditions. Feigl always felt that his spot reactions were a t least as good as other micro-precipitations methods, usually better, never inferior. Some authors have referred to these spot tests as "semi-microanalysis." Feigl never approved of this name. He thought semi-microanalysis referred to identification limits of 10-200 rrg, micrograms, whereas his spot . tests involved identification limits smaller than 10 ~ g In terms of concentration, Feigl's spot tests were effective in many cases into the parts per billion range. Feigl received many prizes and honors from societies and universities all over the world. He received many honors from his adopted country of Brazil, where he was regarded by many as one of the brightest stars in the firmament of Latin American Chemistry.

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