The lot number
It has to match the one printed on your vial, character for character. A certificate from another lot tells you nothing about what you received. This is the check most people skip and the only one that cannot be faked by a nicer PDF.
Buyer's guide
How to read a certificate of analysis
Four checks, about thirty seconds. Do them on our certificates and do them on anyone else's — that is the point.
The four checks
01
02
03
04
In the order that matters
Purity by HPLC
Look for the percentage and the method together. 99% by HPLC is a measurement. 'High purity' with no number and no method is marketing. The chromatogram should be in the document, not just the conclusion.
Identity by mass spec
Purity says how little else is in there. Mass spectrometry says the molecule is the one on the label. You want both: a 99% pure something-else is still the wrong compound.
The lab and the date
A named third-party lab and a test date within the shelf life. A certificate with no date and no letterhead is an image, not a document. If the lab is the seller, it is not third-party testing.
What a certificate actually contains
A certificate of analysis is the lab's report on one specific batch. It is not a quality seal and it is not a licence: it is a measurement, taken on a date, on a sample from a lot. That is exactly what makes it useful — it can be checked.
A complete document carries all of this:
- Lot or batch number — the link between the paper and the vial in your hand.
- Product identity — name, sequence or molecular formula, and molecular weight.
- Purity and method — the number and how it was obtained, usually HPLC, with the chromatogram attached.
- Identity confirmation — mass spectrometry, showing the observed mass against the expected one.
- Appearance and net content — what the material looks like and how much is in the vial.
- Lab, date and signature — who tested it, when, and under whose name.
What a weak certificate looks like
You do not need to be a chemist to spot the common ones:
- A single page with a percentage and nothing else. No chromatogram means nothing to verify.
- No lot number, or a lot number that does not appear on the vial.
- The same PDF served for every product in the catalog.
- A test date older than the shelf life, or no date at all.
- A lab name that returns nothing when you search for it.
A fair warning
A certificate proves what was in one sample of one lot on one date. It does not prove how the material was stored afterwards, and it does not make any compound suitable for any use. It is evidence of purity and identity — nothing more, and nothing less.
How to get the one for your lot
Every product page links the certificate for the lot currently in stock, above the buy button, with the lot number beside it. If you already have a vial, send us the lot printed on the label and we send back that exact document.
If we cannot produce the certificate for a lot, that lot does not ship. There is no version of this where the paperwork arrives later.
Request a certificate
Send the lot number printed on your vial.
For research purposes only
These materials are sold as reference standards for laboratory research. They are not drugs, food or cosmetics. We do not supply dosing information, administration instructions or injection supplies, and we do not sell to anyone stating an intent for human or veterinary use.
Start with the certificate, not the price
Open any product, read its COA, then decide. That is the order we would want if we were buying.