Molekula
Tropaeolin OO
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 2000 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
Tropaeolin OO is a sodium salt of a synthetic azo dye used primarily as a pH indicator and in analytical chemistry for detecting certain metal ions. It appears as a red crystalline powder with a molecular formula of C18H14N3O3SNa and a molecular weight of 375.38 g/mol. It is stable at ambient temperatures and should be handled with care due to its warning signal word. Molekula supplies Tropaeolin OO from research to bulk quantities with full documentation and ISO 9001:2015 traceability.
Example image for illustration only. Other packaging and pack sizes are available.
Pricing & pack sizes
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 — $147.70 per pack
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 |
| Loss on Drying | ≤5% |
| Solubility | Clear solution |
| Absorptivity | (λ max: 442.4nm) ≥600 |
| Visual Transition Interval | From pH 1.2 (red) to pH 2.7 (yellow) |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | Ambient |
| Acidity | Neutral |
Identification
| Property | Value |
|---|---|
| SKU | 23894342 |
| CAS Number | 554-73-4 |
| IUPAC Name | sodium 4-[(4-anilinophenyl)diazenyl]benzenesulfonate |
| EC Number | 209-071-4 |
| Molecular Formula | C18H14N3O3SNa |
| Molecular Weight | 375.38 |
| Exact Mass | 375.0654 |
| SMILES | C1=CC=C(C=C1)NC2=CC=C(C=C2)N=NC3=CC=C(C=C3)S(=O)(=O)[O-].[Na+] |
| InChIKey | MLVYOYVMOZFHIU-UHFFFAOYSA-M |
| InChI | InChI=1S/C18H15N3O3S.Na/c22-25(23,24)18-12-10-17(11-13-18)21-20-16-8-6-15(7-9-16)19-14-4-2-1-3-5-14;/h1-13,19H,(H,22,23,24);/q;+1/p-1 |
| PubChem CID | 23668839 |
| REACH Code | Y110 |
| TSCA Listed | Yes |
| HTS Code | 3212.90.0050 |
| Tariff Code | 3212900000 |
Safety & GHS
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Health Hazard
GHS07
Hazard statements
- H315 Causes skin irritation
- H319 Causes serious eye irritation
- H335 May cause respiratory irritation
Precautionary statements
- P261 Avoid breathing dust/fume/gas/mist/vapours/spray
- P280 Wear protective gloves/protective clothing/eye protection/face protection
- P303+361 IF ON SKIN (or hair): Remove immediately all contaminated clothing. Rinse with water/shower
- P304+340 IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing
- P305+351+338 IF IN EYES: Rinse with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing
- P308+313 IF exposed or concerned: Get medical advice/attention
Documents
Safety Data Sheets (SDS)
Available in English, French, German, Italian, Portuguese, Spanish.
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.
Synonyms
- Acid Orange 5
- C.I. 13080
- C.I. Acid Orange 5
- Diphenylamine Orange
- Orange GS
- Orange IV
- Orange N
- Solar Orange IV
- Tropaeolin
- Tropeolin OO
Frequently asked questions
What is Tropaeolin OO used for?
Tropaeolin OO is primarily used as a pH indicator in analytical chemistry, particularly in strongly acidic media, where it changes from red at about pH 1.4 to yellow at about pH 2.8. It has been used to detect free mineral acid, for example free hydrochloric acid in gastric juice.
What is the chemical formula and molecular weight of Tropaeolin OO?
The formula is C18H14N3O3SNa and the molecular weight is 375.38 g/mol.
How should Tropaeolin OO be stored?
It should be stored at ambient temperature, protected from moisture and light.
What grade of Tropaeolin OO is available?
Molekula supplies Tropaeolin OO in analytical grade.
Can Molekula supply Tropaeolin OO in bulk?
Yes, Molekula can supply Tropaeolin OO in bulk quantities—please contact our sales team for pricing and availability.
What documentation comes with a Tropaeolin OO order?
Each order includes a Certificate of Analysis (CoA) and Safety Data Sheet (SDS) with the shipment.
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.