Schiff's reagent: Difference between revisions
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[[File:Schiffovo_činidlo.png|thumb|Preparation of Schiff's reagent and principle of its reaction with aldehyde]] | |||
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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]]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. | ||
Revision as of 10:52, 19 December 2022
File:Schiffovo činidlo.png
Preparation of Schiff's reagent and principle of its reaction with aldehyde
Schiff's reagent is an aqueous solution of the violet-red dye fuchsinu 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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Source
Leníček M, Muchová L: Organika I
