Molekula
Tropaeolin O
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 1999 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
Tropaeolin O is a sodium salt of a synthetic azo dye used primarily as a pH indicator and in biochemical assays. It appears as a red crystalline powder and is soluble in water. CAS: 547-57-9, Molecular Formula: C12H10N2O5S.Na, Molecular Weight: 316.27 g/mol. Stable at ambient temperature.
Molekula supplies Tropaeolin O in 25 g and 100 g packs, from £61.20 inc. VAT. It is in stock for same-day dispatch. Every batch ships with a certificate of analysis, and a safety data sheet is available. Larger quantities, up to multi-tonne, are quoted on request.
Example image for illustration only. Other packaging and pack sizes are available.
Pricing & pack sizes
In stock — same-day dispatch
These pack sizes aren't a limit. Molekula manufactures, sources and repacks to order — if you need 500 kg and only see 1 kg listed, . We quote from grams to multi-tonne.
Need a different size? Add the nearest pack and change the size in your basket — we price it at the same rate per unit.
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25 g — £51.00 per pack ex VAT · £61.20 inc. VAT
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100 g — £83.50 per pack ex VAT · £100.20 inc. VAT
Need a different quantity or pack?
Tell us how much you need and when — drums, IBCs, sacks or a one-off bulk lot. We'll manufacture or source it and come back with a price.
Prices exclude VAT/sales tax and shipping.
Specifications
| Property | Value |
|---|---|
| Appearance | Orange - brown powder |
| Solubility | Clear, red brown solution |
| Lambda max | 487nm (in 0.1/v sodium hydroxide) |
| Visual Transition Interval | From pH 11.0 (yellow) to pH 12.7 (red) |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | Ambient |
| Acidity | Base |
Identification
| Property | Value |
|---|---|
| SKU | 61804883 |
| CAS Number | 547-57-9 |
| IUPAC Name | sodium 4-[(2,4-dihydroxyphenyl)diazenyl]benzenesulfonate |
| EC Number | 208-924-8 |
| Molecular Formula | C12H10N2O5S.Na |
| Molecular Weight | 316.27 |
| Exact Mass | 316.013 |
| SMILES | C1=CC(=CC=C1N=NC2=C(C=C(C=C2)O)O)S(=O)(=O)[O-].[Na+] |
| InChIKey | COEZWFYORILMOM-UHFFFAOYSA-M |
| InChI | InChI=1S/C12H10N2O5S.Na/c15-9-3-6-11(12(16)7-9)14-13-8-1-4-10(5-2-8)20(17,18)19;/h1-7,15-16H,(H,17,18,19);/q;+1/p-1 |
| PubChem CID | 2728027 |
| REACH Code | Y113 |
| TSCA Listed | Yes |
| HTS Code | 2927.00.30.00 |
| Tariff Code | 2927000090 |
Safety & GHS
Precautionary statements
- P264 Wash thoroughly after handling
- P280 Wear protective gloves/protective clothing/eye protection/face protection
Documents
Certificate of Analysis (CoA) by batch
Enter a lot or batch number to retrieve the CoA for that specific batch. We can generate one from spec data if no PDF is on file.
Quality certificates
Molekula Group is certified to ISO 9001:2015 (quality) and ISO 14001:2015 (environmental management), audited by a UKAS-accredited body. Both certificates are valid to 17 May 2028.
Synonyms
- ACID ORANGE 6
- C.I. Acid Orange 6
- Chrysoine
- Chrysoine Extra
- Chrysoine S
- Chrysonine S
- Resorcin yellow
- Resorcinol yellow
- Tropaeoline
- Tropaeoline O
Frequently asked questions
What is Tropaeolin O used for?
Tropaeolin O is primarily used as a pH indicator in analytical chemistry and as a dye in biochemical assays.
What is the chemical formula and molecular weight of Tropaeolin O?
The formula is C12H10N2O5S.Na with a molecular weight of 316.27 g/mol.
How should Tropaeolin O be stored?
It should be stored at ambient temperature, protected from moisture and light.
What specification does Molekula's Tropaeolin O meet?
Molekula's Tropaeolin O is supplied as an orange-brown powder that gives a clear, red-brown solution, with a lambda max of 487 nm in 0.1 sodium hydroxide and a visual transition interval from pH 11.0 (yellow) to pH 12.7 (red).
Can Molekula supply Tropaeolin O in bulk?
Yes, Molekula can supply Tropaeolin O in bulk quantities upon request.
What documentation comes with a Tropaeolin O order?
Each order includes a Certificate of Analysis (CoA) and safety data sheet (SDS).
Where can I buy Tropaeolin O?
Directly from Molekula, which lists Tropaeolin O in 25 g and 100 g packs from £61.20 inc. VAT, with a certificate of analysis for every batch. Larger quantities are quoted on request. Molekula's offices: United Kingdom, France, Spain, Germany, Italy, United States and China.
Ready to order or need a custom pack?
Tell us the product, grade, and quantity — Molekula usually responds within one working day with pricing and lead time.