Fehling's Reagent

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Related to Fehling's Reagent: Benedict's reagent

Fehling's reagent

[′fāl·iŋz rē‚ā·jənt]
(analytical chemistry)
A solution of cupric sulfate, sodium potassium tartrate, and sodium hydroxide, used to test for the presence of reducing compounds such as sugars.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Fehling’s Reagent


(also Fehling solution, Fehling’s solution), a mixture of equal volumes of a 7-percent solution of copper sulfate and a 34.6-percent solution of potassium sodium tartrate in a 10-percent solution of sodium hydroxide. Fehling’s reagent is used for the qualitative and quantitative determination of aliphatic aldehydes and, especially, monosaccharides. The action of the reagent is based on the reduction of a divalent copper ion to a monovalent ion as a result of the oxidation of the aldehyde (that is, carbonyl) groups of the compounds under study. An orange-yellow precipitate of CuOH is formed at low temperatures; upon heating, a red precipitate of Cu2O is formed. The reagent was proposed in 1850 by the German chemist H. Fehling.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.