Black Eriochrome T - organic compound , direct azo dye with the chemical formula C 20 H 12 N 3 O 7 SNa. Black crystals giving aqueous solutions, the color of which depends on acidity. It is used in analytical chemistry as a complexometric indicator, in microscopy to detect calcium.
| Eriochrome black T | |
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| Are common | |
| Systematic name | (4Z) -4 - [(1-hydroxynaphthalen-2-ylhydrazinylidene] -7-nitro-3-oxo-Y-naphthalene-1-sulfonate |
| Abbreviations | ECCHT, EBT |
| Traditional names | acid chrome black special special black chrome ET-00 black chromogen ET-00 chromogenic black ET calcochrome black T omega-chrome black T or S Pontachrome Black TA black chrome T |
| Chem. formula | C 20 H 12 N 3 O 7 SNa |
| Physical properties | |
| Molar mass | 461.381 g / mol |
| Classification | |
| Reg. CAS number | 1787-61-7 |
| PubChem | |
| Reg. EINECS number | |
| Smiles | |
| Inchi | |
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Content
Physical and chemical properties
Black or brown crystals having greenish fluorescence. It is soluble in alcohol and in water. Aqueous solutions have a different color depending on the acidity of the medium: at pH <6, red, 8-12 - dark blue,> 13 - orange [1] .
During long-term storage it deteriorates: a decrease in optical density is observed, losses during drying increase. Spoiled dye becomes unusable as an indicator [1] .
Application
On the left is a solution of a substance at pH 10, on the right is a color change to red when Ca 2+ |
It is used as a complexometric indicator for the determination of Mg, Mn, Pb, Zn, Cd, In, Zr, and lanthanide ions. In the pH range 9.5-10.0, it has a blue color, and its complexes with calcium, magnesium and zinc ions under the same conditions are red-violet.
In histochemistry, it is used to detect calcium in tissue sections: tissue is stained in bluish colors, calcium deposits in bright red [1] .
Security
Toxic and carcinogenic [1] .
Notes
- β 1 2 3 4 Freistatt, 1980 , p. 455.
Literature
- "Big Encyclopedic Dictionary of Chemistry", Moscow 1998
- "Handbook of Analytical Chemistry" Yu. Yu. Lurie, ed. Chemistry 1971
- Freistat D.S. Reagents and preparations for microscopy. - M .: Chemistry, 1980 .-- 480 p.