Thiobarbituric acid

Structural formula
General
Surname	Thiobarbituric acid
other names	2-thiobarbituric acid 2-Thioxodihydropyrimidin-4,6 (1 H , 5 H ) -dione
Molecular formula	C 4 H 4 N 2 O 2 S
External identifiers / databases
CAS number 504-17-6 EC number 207-985-8 ECHA InfoCard 100.007.260 PubChem 2723628 Wikidata Q418230
properties
Molar mass	144.15 g mol −1
Physical state	firmly
Melting point	235 ° C
solubility	readily soluble in hot water (50 g per liter at 95 ° C)
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 315-319-335 P: 280-305 + 351 + 338
Toxicological data	> 5000 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Thiobarbituric acid is a derivative of barbituric acid . It is used as a reagent in analytical chemistry .

Presentation and extraction

Thiobarbituric acid is produced by reacting thiourea with a malonic acid diester, such as. B. Diethyl malonate .

properties

Thiobarbituric acid forms white crystals with an unpleasant odor. The compound is readily soluble in hot water.

use

In analytical chemistry, thiobarbituric acid is used as a reagent for sorbic acid and for the determination of the biomarker malondialdehyde (MDA). The TBA test (TBA = thiobarbituric acid ) is based on the reaction of thiobarbituric acid with oxidation products of fats, for example malondialdehyde. In this reaction, a pink dye is formed from one molecule of the bifunctional aldehyde with two molecules of thiobarbituric acid, which can be quantified , for example, by photometry .

further reading

• J. Lykkesfeldt: Determination of malondialdehyde as dithiobarbituric acid adduct in biological samples by HPLC with fluorescence detection: comparison with ultraviolet-visible spectrophotometry. In: Clinical chemistry Volume 47, Number 9, September 2001, pp. 1725-1727, PMID 11514418 .
• R. Guillén-Sans, M. Guzmán-Chozas: The thiobarbituric acid (TBA) reaction in foods: a review. In: Critical reviews in food science and nutrition Volume 38, Number 4, May 1998, pp. 315-330, PMID 9626489 .
• DR Janero: Malondialdehyde and thiobarbituric acid-reactivity as diagnostic indices of lipid peroxidation and peroxidative tissue injury. In: Free Radical Biology and Medicine Volume 9, Number 6, 1990, pp. 515-540, PMID 2079232 .
• A. Kolakowska, J. Deutry: Some comments on the usefulness of 2-thiobarbituric acid (TBA) test for the evaluation of rancidity in frozen fish. In: Molecular Nutrition and Food Research Volume 27, Number 5, 1983, pp. 513-518. doi : 10.1002 / food.19830270530 .

Individual evidence

1. ↑ ^{a b c d} Data sheet 2-thiobarbituric acid (PDF) from Merck , accessed on June 13, 2011.
2. ↑ ^{a b} Data sheet thiobarbituric acid from AlfaAesar, accessed on June 14, 2011 ( PDF )(JavaScript required) .
3. ↑ Mertschenk, B .; Knott, A .; Bauer, W .: Thiourea and Thiourea Derivatives , in: Ullmanns Enzyklopädie der Technischen Chemie , Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 2013; doi : 10.1002 / 14356007.a26_803.pub3 .
4. ↑ T. Asakawa, S. Matsushita: Thiobarbituric acid test for detecting lipid peroxides. In: Lipids Volume 14, Number 4, 1979, pp. 401-406. doi : 10.1007 / BF02533425 .