Ninhydrin

Technical Specifications

Product Description & Scientific Applications

Ninhydrin is the hydrate of indane-1,2,3-trione, the central carbonyl held as a stable gem-diol by the two flanking carbonyls. The hydrate is what sits in the bottle; the anhydrous trione is the species that reacts. Light and air darken the solid, so it is kept cool and dark under inert gas.

The colour reaction. Condensation with a primary amine releases carbon dioxide, an aldehyde and ammonia. It delivers Ruhemann's purple alongside hydrindantin. The dye absorbs at 570 nm. Proline and hydroxyproline carry an imino group instead, and give a product absorbing at 440 nm.

Amino acid quantification. Protein hydrolysates are neutralised and their amino acids derivatised with ninhydrin, then read spectrophotometrically at 570 nm.

Peptide synthesis monitoring. The Kaiser test applies ninhydrin with phenol and potassium cyanide to resin beads. A colour change confirms that a coupling step has run to completion.

Thin-layer chromatography. It stains amines, amino acids and aminosugars on developed plates.

Latent fingerprint development. It is among the most used reagents for developing latent prints on porous surfaces. It reacts with the amino acids left in the deposit.

Synthetic building block. With L-proline it condenses to an azomethine ylide. Addition to a dipolarophile gives spiropyrrolizidines in 83–88% yield with good diastereoselectivity.

Shipping Destinations

• EU & UK: Priority delivery, 2–5 business days.
• United States (DDP): 3–7 business days, duties and taxes prepaid.
• EFTA Countries (DDP): 3–7 business days, duties and taxes prepaid.
• Worldwide: 7–14 business days, selected locations.