Ponceau S

This article is about Ponceau S. For other uses, see Ponceau (disambiguation).
Ponceau S
Names
IUPAC name
tetrasodium;3-hydroxy-4-[[2-sulfonato-4-[(4-sulfonatophenyl)diazenyl]phenyl]diazenyl]naphthalene-2,7-disulfonate
Other names
Acid red 112
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.025.745 Edit this at Wikidata
EC Number
  • 228-319-2
UNII
  • Key: KQHKSGRIBYJYFX-UHFFFAOYSA-J
  • InChI=1S/C22H16N4O13S4/c27-22-20(43(37,38)39)10-12-9-16(41(31,32)33)6-7-17(12)21(22)26-25-18-8-3-14(11-19(18)42(34,35)36)24-23-13-1-4-15(5-2-13)40(28,29)30/h1-11,27H,(H,28,29,30)(H,31,32,33)(H,34,35,36)(H,37,38,39)/b24-23+,26-25+
  • OC1=C(N=NC3=CC=C(N=NC4=CC=C(S(=O)(O)=O)C=C4)C=C3S(=O)(O)=O)C2=C(C=C(S(=O)(O)=O)C=C2)C=C1S(=O)(O)=O
Properties
C22H16N4O13S4
Molar mass 672.63 g·mol−1
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H315, H319, H335
P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Ponceau S, Acid Red 112, or C.I. 27195 (systematic name: 3-hydroxy-4-(2-sulfo-4-[4-sulfophenylazo]phenylazo)-2,7-naphthalenedisulfonic acid sodium salt[1]) is a sodium salt of a diazo dye of a light red color, that may be used to prepare a stain for rapid reversible detection of protein bands on nitrocellulose or polyvinylidene fluoride (PVDF) membranes (western blotting), as well as on cellulose acetate membranes.[2] A Ponceau S stain is useful because it does not appear to have a deleterious effect on the sequencing of blotted polypeptides and is therefore one method of choice for locating polypeptides on western blots for blot-sequencing.[2] It is also easily reversed with water washes, facilitating subsequent immunological detection.[2] The stain can be completely removed from the protein bands by continued washing.[2] Common stain formulations include 0.1% (w/v) Ponceau S in 5% acetic acid or 2% (w/v) Ponceau S in 30% trichloroacetic acid and 30% sulfosalicylic acid.[3]

A nitrocellulose membrane stained with Ponceau S dye for protein detection during western blotting. The blue bands on the left are protein markers for various molecular weights.
  1. ^ "Ponceau S solution". Sigma-Aldrich. Retrieved 2016-11-24.
  2. ^ a b c d Al-Amoudi, M. S.; Salman, Mahmoud; Al-Majthoub, M. M.; Adam, Abdel Majid A.; Alshanbari, Naif A.; Refat, Moamen S. (9 October 2013). "Spectral studies to increase the efficiency and stability of laser dyes by charge-transfer reactions for using in solar cells: charge-transfer complexes of Ponceau S with p-chloranil, chloranilic and picric acids". Research on Chemical Intermediates. 41 (5): 3089–3108. doi:10.1007/s11164-013-1417-4. S2CID 96999885.
  3. ^ "Ponceau S solution". Sigma-Aldrich. Retrieved 2016-11-24. The following are two common stain formulations…