Showing papers by "Fritz Feigl published in 1956"
13 citations
9 citations
TL;DR: The erreichbaren erfassungsgrenzen (auf Kohlenstoff bezogen) liegen zwischen 0.5 and 8μg as mentioned in this paper.
Abstract: Beim Erhitzen trockener Gemische organischer Verbindungen mit Kaliumjodat oder Molybdan(VI)-oxyd erfolgen Redoxreaktionen, wobei Kaliumjodid bzw. Molybdanblau entsteht. Da diese Reaktionsprodukte leicht erkennbar sind, kann die Sinteroxydation in der Tupfelanalyse zum Nachweis von Kohlenstoff und organischen Verbindungen verwendet werden. Die erreichbaren Erfassungsgrenzen (auf Kohlenstoff bezogen) liegen zwischen 0,5 und 8μg.
6 citations
TL;DR: Anhydrous hydrogen chloride, which is far more reactive than concentrated aqueous hydrochloric acid, is formed when solid zinc chloride or evaporation residues of its solutions are heated.
Abstract: Anhydrous hydrogen chloride, which is far more reactive than concentrated aqueous hydrochloric acid, is formed when solid zinc chloride or evaporation residues of its solutions are heated. Certain reactions, which cannot be accomplished with the concentrated aqueous acid, can be realized by fusion with zinc chloride. Detection of calcium, magnesium, ferrous iron, nickel, and potassium in silicates; differentiation of niobium and tantalum pentoxides, can be based on the ready decomposition of silicates and on a redox reaction of niobium pentoxide. Fusion with zinc chloride can release ferrous iron from acid-resistant minerals that contain no silica. All of these processes can be accomplished with slight amounts of sample and within the technique of spot test analysis.
6 citations
5 citations
3 citations
TL;DR: In this paper, azo dyes containing a p-phenylenediamine or p-nitroaniline structure are fused with a dry mixture of sodium formate and sodium hydroxide at 210-230°C.
Abstract: When Bandrowski's base and azo dyes containing a p-phenylenediamine or a p-nitroaniline structure are fused with a dry mixture of sodium formate and sodium hydroxide at 210–230°C. p-phenylenediamine is formed by reductive cleavage. Under these conditions the diamine sublimes and the vapour reacts with an acetic-acid solution of aniline and alkali-metal persulphate to yield the indamine dye Phenylene Blue. This procedure may be conducted by the technique of spot test analysis and serves to detect such dyes. The detection limits are in the range 5–10 μg., as has been verified by testing thirteen pertinent compounds.
2 citations
TL;DR: In this article, a new and sensitive test for free sulfur in mixtures with organic or inorganic substances is proposed, which is done in a test-tube, whose mouth carries lead acetate paper.
Abstract: Hydrogen sulfide is formed when free sulfur is heated with fused benzoin. This is the basis of a new and sensitive test for free sulfur in mixtures with organic or inorganic substances. The heating is done in a test-tube, whose mouth carries lead acetate paper. The limit of identification is 0.5µ. Selenium does not interfere. Tests of a wide variety of commercial products gave satisfactory results.
1 citations