Seliwanoff

By careful choice of both the reaction conditions and the phenolic compound used, it may be possible to produce a colour that is characteristic of a particular carbohydrate or related group, so giving some degree of specificity to the method. Thus, Seliwanoff s test uses hydrochloric acid and either resorcinol or 3-indolylacetic acid to measure fructose with minimal interference from glucose. The colour produced by pentoses with orcinol (Bial s reagent) or p-bromoaniline is sufficiently different from that produced by hexoses to permit their quantitation in the presence of hexoses. However, none of the methods based on the formation of furfural or its derivatives can be considered to be entirely specific. 

Seliwanoff s test analy chem A color test helpful in the identification of ketoses, which develop a red color with resorcinol in hydrochloric acid. s3 liv3,nofs, test sellite liNORG chem A solution of sodium sulfite (Na2S03) used in the purification of 2,4,6-trinitrotoluene to remove unsymmetrical isomers. se,lTt ... 

On oxidation of 1 mole of planteose by periodic acid, 4.6 moles of oxidant were consumed, with the formation of 1.8 moles of formic acid (no formaldehyde was produced). After treating the oxidized product with an excess of sodium borohydride, the Seliwanoff test for fructose was negative, though a similarly oxidized and reduced sample of melezi-tose gave a positive fructose test. 

There are a number of well-known tests for carbohydrates which depend on color formation. Thus in the Molisch test the substance is treated with mineral acid in the presence of a-naphthol and a characteristic purple color is formed. In Seliwanoff s test only ketoses give an immediate red color when warmed with mineral acid and resorcinol, and similarly ketoses give a blue coloration when warmed with sulfuric acid and diphenylamine in the Ihl-Pechmann reaction. 

Seliwanoff s test A test for ketose SUGARS in solution. The reagent used consists of resorcinol dissolved in hydrochloric acid. A few drops are added to the solution and a red precipitate indicates a ketonic sugar. The test is named for the Russian chemist F. F. Seliwanoff. 

Seliwanoff s test A biochemical test to identify the presence of ketonic sugars, such as fructose, in solution. It was devised by the Russian chemist F. F. Seliwanoff. A few drops of the reagent, consisting of resorcinol crystals dissolved in equal amounts of water and hydrochloric acid, are heated with the test solution and the formation of a red precipitate indicates a positive result. 

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