Molekula
o-Phthaldialdehyde
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
o-Phthaldialdehyde (OPA) is a highly reactive aromatic aldehyde primarily used in fluorescence-based assays for amino acid and protein detection, as well as in organic synthesis. It forms highly fluorescent adducts with primary amines under alkaline conditions, making it ideal for analytical and biochemical applications. Beyond the laboratory, it is used as a disinfectant for sterilizing medical and dental equipment and as a biocide in water treatment and pulp and paper processing. This chemical has a CAS number of 643-79-8, with a molecular formula of C8H6O2 and a molecular weight of 134.13. It must be stored between 2 to 8°C and carries a **Danger** signal word due to its hazardous properties. Molekula supplies o-Phthaldialdehyde 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.
Often bought together
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 — £69.90 per pack ex VAT · £83.88 inc. VAT
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100 g — £233.00 per pack ex VAT · £279.60 inc. VAT
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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 | Pale/light yellow crystals |
| Melting Point | 54°C to 57°C |
| Water | ≤0.5% |
| Identification | Conforms to reference |
| Assay (GC) | ≥ 98.0% |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | 2 to 8 °C |
| Flash Point | 132 °C |
| Transport Class | 8(6.1) |
| Packing Group | II |
| Acidity | Neutral |
Literature values
Published physical properties of the substance, not batch specifications.
| Property | Value |
|---|---|
| Melting Point | 55.8 °C |
| Solubility (other solvents) | Very soluble in ethyl ether, ethanol |
| Vapour Pressure | 0.6 Pa at 25 °C |
| log P (octanol/water) | 0.51 |
Source: PubChem CID 4807 (HSDB, ICSC)
Identification
| Property | Value |
|---|---|
| SKU | 29247150 |
| CAS Number | 643-79-8 |
| IUPAC Name | phthalaldehyde |
| EC Number | 211-402-2 |
| Molecular Formula | C8H6O2 |
| Molecular Weight | 134.13 |
| Exact Mass | 134.0368 |
| SMILES | C1=CC=C(C(=C1)C=O)C=O |
| InChIKey | ZWLUXSQADUDCSB-UHFFFAOYSA-N |
| InChI | InChI=1S/C8H6O2/c9-5-7-3-1-2-4-8(7)6-10/h1-6H |
| PubChem CID | 4807 |
| UN Number | UN2923 |
| REACH Code | Y110 |
| TSCA Listed | Yes |
| Tariff Code | 32129000 |
Safety & GHS
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Corrosive
GHS05
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Toxic
GHS06
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Health Hazard
GHS07
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Hazardous to the Environment
GHS09
Hazard statements
- H301 Toxic if swallowed
- H314 (sub cat. 1B) Causes severe skin burns and eye damage
- H317 May cause an allergic skin reaction
- H335 May cause respiratory irritation
- H400 Very toxic to aquatic life
- H410 Very toxic to aquatic life with long lasting effects
Precautionary statements
- P273 Avoid release to the environment
- P280 Wear protective gloves/protective clothing/eye protection/face protection
- P301+330 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting
- P305+351+338 IF IN EYES: Rinse with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing
- P310 Immediately call a POISON CENTER or doctor/physician
- P501 Dispose of contents/container to an approved waste disposal plant
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
- 1,2-Benzenedicarboxaldehyde
- benzene-1,2-dicarbaldehyde
- o-Phthalaldehyde
- ortho-Phthalaldehyde
- PHTHALALDEHYDE
- Phthalaldialdehyde
- Phthalic aldehyde
- Phthalic dialdehyde
- Phthalic dicarboxaldehyde
- Phthalyldicarboxaldehyde
Frequently asked questions
What is o-Phthaldialdehyde (CAS 643-79-8) commonly used for?
o-Phthaldialdehyde is primarily used in fluorescence labeling, particularly for amino acids and peptides in biochemical research, and as a reagent in HPLC derivatization for improved detection.
What is the chemical formula and molecular weight of o-Phthaldialdehyde?
The chemical formula is **C₈H₆O₂**, and the molecular weight is **134.13 g/mol**.
How should o-Phthaldialdehyde be stored?
Store at **2–8°C** in a cool, dry place, protected from light and moisture. Avoid prolonged exposure to air.
What purity grades of o-Phthaldialdehyde does Molekula supply?
Molekula supplies **analytical and reagent-grade o-Phthaldialdehyde**, typically ≥98% purity for research applications.
Can Molekula supply o-Phthaldialdehyde in bulk quantities?
Yes, we offer bulk packaging options for o-Phthaldialdehyde upon request, subject to availability and order volume.
What documentation is provided with an order of o-Phthaldialdehyde?
Each order includes a **Certificate of Analysis (CoA)**, Safety Data Sheet (SDS), and batch-specific documentation for traceability.
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.