Every vial of research material should come with a certificate of analysis — a COA. Most vendors say they have them. Fewer will show you one. Almost none let you check it against the laboratory that supposedly issued it.
This page explains what a COA contains, what each line means, and how to verify that the document in front of you is real. It works for any vendor’s certificate, not just ours. If it helps you decide to buy from someone else, that’s a good outcome.
Start here: is the document even real?
Before reading a single test result, establish that the certificate hasn’t been altered. A COA is a PDF. PDFs are trivially easy to edit. A purity figure of 87% becomes 97% with about ten seconds of work, and the edited file looks identical to the original.
There are three levels of assurance, and the difference between them is large.
A typed PDF. Someone produced a document that says a laboratory tested something. There is no way to confirm the lab ever saw the material. This is the most common thing in the industry and it is worth very little.
A scanned or letterheaded PDF. Better in appearance, no better in substance. Letterheads can be copied.
A digitally signed PDF. The laboratory signs the file cryptographically when it issues the certificate. If a single character changes afterward — a number, a date, a lot code — the signature breaks. Your PDF reader will tell you.
How to check a digital signature
- Open the certificate in Adobe Acrobat Reader. Free, and it’s the reader that handles signatures properly. Browser PDF viewers often don’t display signature information at all.
- Look at the top of the document. A signed file shows a banner: either “Signed and all signatures are valid” or a warning that the document has been modified.
- Open the Signature Panel (usually a button in that banner, or View → Show/Hide → Navigation Panes → Signatures).
- The panel names who signed it, when, and whether the document has changed since.
If the panel says the document has been modified since signing, stop. That is a definitive answer, not an ambiguous one.
If there is no signature at all, you are relying entirely on the vendor’s word. That may be fine. But you should know that’s what you’re doing.
Check the lot number independently
A signature proves the document is unaltered. It doesn’t prove the document belongs to the vial in your hand.
Every vial should carry a lot number on its label. That number should appear on the certificate. And ideally you should be able to enter that lot number on the laboratory’s own site and see the same result — without going through the vendor at all.
Our certificates are issued and digitally signed by Purity Analytics in Georgia, USA, and each lot can be looked up at verify.purityanalytics.com. Other labs offer similar lookups; Janoshik, for instance, publishes reports by report ID. If a vendor’s lab offers no independent lookup, ask why.
The tests, line by line
A complete panel answers five separate questions. Many certificates answer only the first one.
1. Purity — HPLC
What it asks: of everything in this vial, what percentage is the compound it’s supposed to be?
Method: high-performance liquid chromatography. The sample is pushed through a column that separates its components, and each component registers as a peak. The target compound’s peak is measured against the total.
What to look for: a percentage, usually reported to one decimal place, and ideally the chromatogram itself — the actual graph. A single number with no chromatogram is a claim; the graph is the evidence. Look at whether the main peak is clean and symmetrical, and how much area sits in the smaller peaks around it.
Common figures: research-grade material is typically reported at 98% or above. Be a little suspicious of 100.0%. Analytical methods have limits of detection, and a perfectly round number sometimes indicates a rounded, or invented, one.
What it does not tell you: what the compound is. Purity says one substance dominates the sample. It doesn’t say which substance. That’s the next test.
2. Identity — mass spectrometry
What it asks: is this actually the compound named on the label?
Method: mass spectrometry measures the molecular weight of what’s in the vial. Every peptide has a known theoretical mass based on its sequence. The measured mass should match.
What to look for: an observed mass and a theoretical mass, and they should agree to within a fraction of a percent. Some certificates report the sequence as well.
Why it matters more than purity: a sample can be 99% pure and be 99% the wrong molecule. Purity without identity is close to meaningless, and identity is the test most often missing from a thin certificate.
3. Endotoxin — LAL
What it asks: does the material contain bacterial endotoxins?
Method: the limulus amebocyte lysate assay, which reacts to lipopolysaccharides from gram-negative bacteria.
What to look for: a result in EU/mg (endotoxin units per milligram) with a specification it’s measured against. Endotoxins survive sterilization, so a sterile sample is not automatically a low-endotoxin sample.
Why it’s on the panel: endotoxin contamination affects experimental results in ways that look like real biological effects. In cell culture work particularly, it’s a well-documented source of confounded data.
4. Microbial content — TAMC and TYMC
What it asks: are bacteria or fungi growing in this material?
Method: total aerobic microbial count and total yeast and mould count. Samples are cultured and colonies counted.
What to look for: results expressed as CFU/g against a specification. Lyophilized peptides should show very low counts.
5. Heavy metals — ICP-MS
What it asks: are there toxic metals present, and at what concentration?
Method: inductively coupled plasma mass spectrometry, which detects elements at parts-per-billion levels. Typically reports lead, arsenic, cadmium and mercury.
What to look for: each element listed with its result and limit. Heavy metals enter through synthesis reagents, catalysts, and glassware, so this test says something about the manufacturing process itself, not just the final material.
Reading the header
The results are only half the document. The header tells you whether the results apply to what you have.
Lot or batch number. Must match the vial label. A certificate for a different lot tells you about material you don’t have. This is the single most common way a genuine certificate gets used misleadingly.
Date of analysis. Should be reasonably close to when the lot was produced. A certificate from three years ago attached to a recently sold vial is worth asking about.
Sample identity. What the lab was told it was testing, and what quantity.
The laboratory. A name, a location, and ideally accreditation. An unnamed “third-party lab” is not a third party in any meaningful sense.
Who requested the test. Usually the manufacturer or the vendor. Worth knowing, because it tells you who chose which sample to send.
What a certificate cannot tell you
Honest limits, because a page that only lists strengths isn’t useful.
It describes one sample from one lot. The lab tested what it was sent. Consistency across lots is a question about the vendor’s process, not about any single certificate.
It says nothing about storage or handling after testing. A peptide that was analyzed correctly and then shipped warm, or stored badly, is no longer the material described.
It says nothing about whether the compound works. A COA is an analytical document. The question of what the published literature says about a compound is separate, and that’s what the rest of this library is for.
It doesn’t prove the vendor sends you the lot it tested. This is why lot numbers on labels matter, and why independent lookup at the lab matters more than the certificate itself.
A short checklist
Before you order from any supplier, including us:
- Is a certificate available before purchase, or only after?
- Is it digitally signed, and does the signature verify?
- Does the lot number on the certificate match the vial’s label?
- Can you look that lot up at the laboratory’s own site?
- Does the panel include identity, or only purity?
- Is the laboratory named, with a location?
- Is the date of analysis recent enough to be relevant?
A supplier who can answer all seven is being straightforward with you. A supplier who can’t answer any is telling you something too.
About this page
This library is published by Agape Compounds LLC, which also supplies research-use-only compounds. It is written to be useful regardless of where you buy. Our own certificates are issued and digitally signed by Purity Analytics; since spring 2026 every new lot is signed this way, and a few older lots still carry certificates from our previous laboratory — the QR code on each vial shows which.
All products are sold for research use only and are not for human or animal use.
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