A test result, tied to a batch
A certificate of analysis reports what an analytical laboratory found when it examined a specific production batch. Not the product line, not a typical sample: that batch, identified by number.
Two findings carry most of the weight. Identity establishes which compound is present, generally by mass spectrometry, which measures molecular mass against what the sequence predicts. Purity establishes what proportion of the sample is that compound, generally by HPLC, which separates the components and measures their relative abundance.
Everything else on the document, appearance, water content, residual solvents, is supporting detail. If identity and purity are not both there and both legible, the rest is decoration.
One qualification applies to identity. A mass measurement confirms that the molecule weighs what the sequence predicts, which rules out the wrong compound and most truncated chains; it does not by itself distinguish two sequences built from the same residues in a different order, because those weigh the same. The methods literature on PubMed covers how fragmentation data closes that gap. For a buyer the practical point is that a laboratory which reports how it confirmed identity is telling you more than one which reports a bare mass.
Four checks in order
Work through these before anything else on the page.
No approval process sits behind this material
Research compounds do not go through the regulatory review that licensed medicines do. Nobody outside the supply chain has verified what is in the vial before it reaches you.
That makes the certificate the entire verification layer. It is not a marketing document or a trust signal; it is the only mechanism by which a claim about the contents becomes checkable.
We release at 99% minimum by HPLC and the certificate for your batch is available on request. If any supplier, including us, becomes vague when you ask for it, treat that as the answer to your question.
A certificate also has a shelf life of its own kind. It describes the batch as tested, not the vial after months in a warm drawer or a solution that has been frozen and thawed repeatedly, so the storage page and the freeze-thaw page are the other half of knowing what is in the container. The document tells you what left the laboratory; handling decides what is still there.
- No batch numberA certificate that cannot be tied to the vial in your hand proves nothing about the vial in your hand.
- Purity without a chromatogramThe trace is the evidence. A percentage on its own is a claim someone typed.
- The same document for every orderBatches vary. One certificate reused across a product line means nobody is testing per batch.
- No laboratory namedAn unnamed lab cannot be contacted, checked or held to anything.
Related reading
Three pages that follow directly from this one.
About certificates
What people ask before requesting one.