Ponceau S.
Structural formula | |||||||||||||||||||
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CI Acid Red 112 as a free acid | |||||||||||||||||||
General | |||||||||||||||||||
Surname | Ponceau S. | ||||||||||||||||||
other names | |||||||||||||||||||
Molecular formula | C 22 H 12 N 4 Na 4 O 13 S 4 | ||||||||||||||||||
External identifiers / databases | |||||||||||||||||||
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properties | |||||||||||||||||||
Molar mass | 760.57 g mol −1 (672.64 g mol −1 , free acid) | ||||||||||||||||||
safety instructions | |||||||||||||||||||
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As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . |
Ponceau S is a red bisazo dye from the application group of acid dyes , which is often used to reversibly stain proteins on a nitrocellulose or PVDF membrane.
use
In Western blotting , the dye is used to check whether protein has been transferred to the membrane . Ponceau S binds reversibly to the positively charged amino groups of the proteins. A Ponceau-S stain is very easy to wash out with water to remove the membrane e.g. B. to continue to be used for immunodetection with antibodies .
A widely used recipe for coloring is 0.1% Ponceau S in 5% acetic acid or 2% Ponceau S in 30% trichloroacetic acid and 30% 5-sulfosalicylic acid (2-hydroxy-5-sulfobenzoic acid).
Individual evidence
- ↑ a b Datasheet Ponceau S from Sigma-Aldrich , accessed on April 21, 2011 ( PDF ).