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[[File:Schiffovo_činidlo.png|thumb|Preparation of Schiff's reagent and principle of its reaction with aldehyde]]
[[File:Preparation of Schiff's reagent and principle of its reaction with aldehyde.png|thumb|Preparation of Schiff's reagent and principle of its reaction with aldehyde]]
Schiff's reagent is an aqueous solution of the violet-red dye [[fuchsin]]u to which bisulfite or sulfite is added. Hydrogen sulphite is adducted to the central carbon atom, thereby disrupting the quinoid structure that conditions the colour. A colorless fuchsin sulfuric acid solution is formed. After adding even a small amount of aldehyde, sulfuric acid is released from the bond to fuchsin, which binds to the aldehyde group with a stronger bond. In the fuchsin molecule, the quinoid structure is restored and the solution turns violet-red again.
Schiff's reagent is an aqueous solution of the violet-red dye [[fuchsin]] to which bisulfite or sulfite is added. Hydrogen sulphite is adducted to the central carbon atom, thereby disrupting the quinoid structure that conditions the colour. A colorless fuchsin sulfuric acid solution is formed. After adding even a small amount of aldehyde, sulfuric acid is released from the bond to fuchsin, which binds to the aldehyde group with a stronger bond. In the fuchsin molecule, the quinoid structure is restored and the solution turns violet-red again.


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Latest revision as of 10:56, 19 December 2022

Preparation of Schiff's reagent and principle of its reaction with aldehyde

Schiff's reagent is an aqueous solution of the violet-red dye fuchsin to which bisulfite or sulfite is added. Hydrogen sulphite is adducted to the central carbon atom, thereby disrupting the quinoid structure that conditions the colour. A colorless fuchsin sulfuric acid solution is formed. After adding even a small amount of aldehyde, sulfuric acid is released from the bond to fuchsin, which binds to the aldehyde group with a stronger bond. In the fuchsin molecule, the quinoid structure is restored and the solution turns violet-red again.


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Leníček M, Muchová L: Organika I