DNPH

DNP test

DNPH is a reagent in instructional analytical chemistry laboratories. Brady's reagent or Borche's reagent, is prepared by dissolving DNPH in a solution containing methanol and some concentrated sulfuric acid. This solution is used to detectketones and aldehydes. A positive test is signalled by the formation of a yellow, orange or red precipitate of the dinitrophenylhydrazone. Aromatic carbonyls give red precipitates whereas aliphatic carbonyls give more yellow color. The reaction between DNPH and a generic ketone to form a hydrazone is shown below: