Benedict's reagent

The Benedict 's reagent is a reagent that is used in the organic chemistry for the detection of reducing sugars, flavonoids and coumarins. It was invented in 1908 by the American chemist Stanley Benedict.

Composition

The reagent consists of two solutions. The first solution contains sodium ( the sodium salt of citric acid), and sodium carbonate, which are dissolved in water. A second solution of copper ( II) sulfate in water is added. The replacement of hydroxide carbonate by the reagent is less corrosive and by the use of citrate instead of tartrate it is more stable than the Fehling reagent.

Proof

Benedict the reagent is used as the Fehling's reagent for the detection of reducing sugars, flavonoids and coumarins. In the solution, then falls from a precipitate, which is red, yellow or green depending on the sugar concentration.

Reaction scheme

Formally, the organic compound is oxidized by the copper ions. It forms copper (I ) hydroxide and the corresponding organic compound, using the example of an aldehyde as:

The reaction must take place in the alkaline range.