Answer to Question #28460 in Inorganic Chemistry for merlin

Question

which of the following stains are suitable for detecting amino acids on a silica plates and give reason for the answer?
1 Ninhydrin
2 Aniline phthalate
3 Charring with 30% sulphuric acid
4 Pauly stain
5 Dragendorf reagent

Answer 1

1Ninhydrin

Ninhydrin reaction, color reaction to a-amino acids, which is carried out byheating the latter in excess of an alkaline solution of ninhydrin and forms compounds that are violet-blue color. Proline and hydroxyproline, which do not have a-amino groups in the reaction with ninhydrin derivative form yellow. Ninhydrin reaction is not specific, since the colored product with ninhydrin give as NH₃, etc. Comm. Containing amino group (including proteins and peptides). However, reactions to these Comm. performed without CO₂ emissions, and ninhydrin reaction with CO₂ is specific for a-amino acids.