Ninhydrin hydrate
[CAS# 485-47-2]

Identification

• Classification: Pharmaceutical intermediate >> Heterocyclic compound intermediate >> Pyrimidine compound >> Ketones
• Name: Ninhydrin hydrate
• Synonyms: Ninhydrin monohydrate; 1,2,3-Indantrione monohydrate; 2,2-Dihydroxy-1,3-indanedione; Trioxohydrindene monohydrate
• Molecular Formula: C₉H₆O₄
• Molecular Weight: 178.14
• CAS Registry Number: 485-47-2
• EC Number: 207-618-1
• SMILES: C1=CC=C2C(=C1)C(=O)C(C2=O)(O)O

Properties

• Density: 0.862
• Melting point: 250 °C
• Water solubility: 0.1-0.5 g/100 mL at 20 °C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319
• Safety Statements: P264-P270-P280-P301+P312+P330-P302+P352-P305+P351+P338-P332+P313-P337+P313-P362+P364-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H302
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin sensitization	Skin Sens.	1B	H317
Eye irritation	Eye Irrit.	2A	H319
Acute toxicity	Acute Tox.	4	H312
Respiratory sensitization	Resp. Sens.	1	H334
Acute toxicity	Acute Tox.	4	H332
Specific target organ toxicity - single exposure	STOT SE	3	H336
Skin sensitization	Skin Sens.	1	H317
Flammable liquids	Flam. Liq.	2	H225
Acute toxicity	Acute Tox.	3	H301

Discovery and Applications

Ninhydrin hydrate is a key compound widely used in analytical chemistry and forensics. Its unique reactivity and applications make it an important tool in various fields.

Ninhydrin, or 2,2-dihydroxy-1,3-dione, was first synthesized by German chemist Rudolf Schmitt in the early 20th century. Its ability to react with amino acids has enabled significant advances in biochemical analysis. Ninhydrin hydrate is the hydrated form of ninhydrin and usually occurs as a crystalline powder containing water molecules.

Ninhydrin hydrate is used in a variety of analytical and forensic applications due to its ability to react with primary and secondary amines. Upon reaction with amines, ninhydrin undergoes a color change to form a complex known as Luhrmann purple. This reaction is highly sensitive and specific, making it a valuable tool in different analytical techniques.

Ninhydrin hydrate is widely used to detect proteins and amino acids. In paper chromatography and other separation techniques, ninhydrin reacts with amino acids to form colored complexes that can then be visualized and quantified. This application is critical in biochemical studies and determining the amount of protein in a sample.

In forensic science, ninhydrin hydrate is used to reveal latent fingerprints. When applied to a surface, ninhydrin reacts with the amino acids in the fingerprint residue to produce a purplish-blue color, which enhances the visibility of the fingerprint. This technique is essential for fingerprint analysis and evidence collection in criminal investigations.

Ninhydrin hydrate is used to detect and quantify free amino groups in a variety of chemical and biological samples. Its ability to form colored complexes with amino groups makes it a valuable reagent in chemical analysis and research.

In a laboratory setting, ninhydrin hydrate is used to assess the purity of proteins. By analyzing the intensity of the color produced in the reaction, researchers can determine the presence of contaminants or assess the extent of protein degradation.

Ninhydrin hydrate has been used in historical and archaeological research to analyze ancient biological samples. Its sensitivity to amino acids allows researchers to detect and study protein and other biomolecular residues in artifacts and fossils.

Ninhydrin hydrate has a high sensitivity in detecting amino acids and proteins, which is essential for accurate analysis and detection in a variety of applications. The versatility of this compound in detecting both primary and secondary amines makes it suitable for use in a wide range of fields, from forensic science to biochemical research. The color change produced when ninhydrin hydrate reacts with amines is easily visualized and quantified, allowing for direct analysis.

References

1991. A New Method for Carbon Isotopic Analysis of Protein. Science (New York, N.Y.), 251(4994).
DOI: 1990430

1979. A simplified procedure for the quantitative extraction of lipids from brain tissue. Lipids, 14(6).
DOI: 459723

1970. The molecular constancy of fibrinopeptides A and B from 125 individual humans. Humangenetik, 9(3).
DOI: 4988845