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单词 ninhydrin reaction
释义

Ninhydrin Reaction


Ninhydrin Reaction

 

a color reaction used for the qualitative and quantitative identification of amino acids, imino acids, and amines. Upon heating in an alkaline medium with substances containing primary amino groups (— NH2), ninhydrin (triketohydrindene hydrate, C9H6O4) yields a product with a stable deep blue-violet color, with maximum absorption at about 570 nanometers. Since absorption at this wavelength is a linear function of the number of free amino groups, the ninhydrin reaction is the primary means of quantitative identification of amino groups in colorimetry and spectrophotometry. The ninhydrin reaction is also used to detect secondary amino groups (> NH) in imino acids (proline and hydroxyproline); a bright yellow product is obtained as a result of the test.

The sensitivity of the ninhydrin reaction is up to 0.01 percent. Modern automatic amino-acid analysis is carried out by combining the ion-exchange separation of amino acids and their quantitative identification using the ninhydrin reaction. The reaction is also used to detect each type of amino acid present in quantities no smaller than 2–5 micrograms when techniques of paper chromatography are used to separate mixtures of amino acids.

E. N. SAFONOVA

ninhydrin reaction


nin·hy·drin re·ac·tion

a test for proteins, peptones, peptides, and amino acids possessing free carboxyl and α-amino groups that is based upon the reaction with triketohydrindene hydrate; a blue color reaction is used to quantitate free amino acids (for example, after hydrolysis and separation of the amino acids of a protein). Synonym(s): triketohydrindene reaction

nin·hy·drin re·ac·tion

(nin-hī'drin rē-ak'shŭn) A procedure for proteins, peptones, peptides, and amino acids possessing free carboxyl and α-amino groups that is based on the reaction with triketohydrinene hydrate; a blue color reaction is used to quantitate free amino acids.
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更新时间:2025/3/4 11:22:19