The Schiff test invented and named after Hugo Schiff

Hugo Schiff

Hugo Schiff was a German Chemist. He discovered Schiff bases and other imines, and was responsible for research into aldehydes and had the Schiff test named after him. He also worked in the field of amino acids and the Biuret reagent.Born in Frankfurt am Main, Schiff was a student of Friedrich...

 is a chemical test

Chemical test

In chemistry, a chemical test is a qualitative or quantitative procedure designed to prove the existence of, or to quantify, a chemical compound or chemical group with the aid of a specific reagent...

 for the detection of aldehydes. An unknown sample is added to the decolorized Schiff reagent and when aldehyde is present a characteristic magenta

Magenta

Magenta is a color evoked by light stronger in blue and red wavelengths than in yellowish-green wavelengths . In light experiments, magenta can be produced by removing the lime-green wavelengths from white light...

 or purple color develops. The Schiff reagent is the reaction product of Fuchsine

Fuchsine

Fuchsine or rosaniline hydrochloride is a magenta dye with chemical formula C20H19N3·HCl. There are other similar chemical formulations of products sold as fuchsine, and several dozen other synonyms of this molecule....

 or the closely related Pararosaniline

Pararosaniline

Pararosaniline, Basic Red 9, or C.I. 42500 is a magenta dye having chemical formula 19183. It is one of the four components of basic fuchsine. Pararosaniline, which is sold as a single dye, may make the best Schiff's reagent...

 (lacks a methyl group) and sodium bisulfite

Sodium bisulfite

Sodium bisulfite is a chemical compound with the chemical formula NaHSO3. Sodium bisulfite is a food additive with E number E222. This salt of bisulfite can be prepared by bubbling sulfur dioxide in a solution of sodium carbonate in water...

. Human skin also contains aldehydes and gets stained as well.

Schiff reagents are used for various staining methods, e.g.