Reviewed August 2026 by the Corydalis Labs Technical Team. How we research and review.
Why this is worth ten minutes of your time
You are buying a white powder whose identity you cannot verify by looking at it, from a supplier you likely found online, in a category where the cheaper adjacent compound is chemically similar enough to pass a casual glance.
The certificate of analysis is the entire mechanism protecting you from that. If you cannot read one properly, you do not have the protection — you have a PDF.
What a useful certificate contains
- A lot code that matches your container. If the certificate does not identify the specific lot, it is describing something other than what you received.
- The identity of the compound, and how identity was established. A name alone is a claim. A name plus a method is a result.
- An assay figure — the percentage of the specified compound — again with the method that produced it.
- A date. Both when the material was produced and when it was tested.
- Contaminant results where your specification requires them — heavy metals, microbiological, residual solvents, depending on the material and your market.
- Something that lets you go further — a chromatogram on request, method parameters, a named lab.
What should make you suspicious
Warning signs
- No method stated. "13-OH: 97%" tells you what someone typed, not what an instrument measured.
- No lot code, or a lot code that does not match your container.
- An undated document, or one reused across shipments.
- Round numbers every time. Real assays land on untidy figures. A supplier whose material is 98% in every lot forever is either extraordinary or not measuring.
- Reluctance to provide a chromatogram or method parameters. There is no confidential reason to withhold either from a customer.
- Discouraging third-party testing. This is the loudest signal available, and it is usually dressed as concern about method differences.
Specific to this category
For corydalis-derived material there is one question that matters more than the rest: can this certificate distinguish 13-OH from its parent alkaloid?
Tetrahydropalmatine is cheaper and more widely available. The two compounds separate cleanly under standard reverse-phase HPLC — in our method the parent elutes at 15.0 minutes and 13-OH at 18.8 — so the analysis is neither difficult nor expensive. But it only protects you if someone actually runs it and the certificate reflects that.
Ask any supplier, including us: what method establishes identity, what are the retention times, and will you send the chromatogram? A supplier who cannot answer that quickly is not testing. Our method is published.
The questions that get honest answers
- "What method established identity, and what are the retention times?" Tests whether analysis happened.
- "Can you send the chromatogram for this lot?" Tests whether the data exists.
- "Will you share your method parameters so my lab can reproduce it?" Tests confidence.
- "How much does assay vary between lots?" Tests whether they are measuring or reciting.
- "Any objection to me sending a retain to an independent lab?" The answer to this one tells you almost everything.
None of these is aggressive and none should cause friction with a supplier who is doing the work. If they do cause friction, that is your answer.
Do it once yourself
Whatever a certificate says, send material to an independent lab once at the start of a supplier relationship. It is a modest cost against the risk of building a production run on the wrong compound, and it converts a document you are trusting into a fact you have verified.
We say this knowing customers will apply it to us. That is the point — a supplier whose material survives independent testing has a stronger position afterwards than one who was simply believed. Our testing programme, and how to verify it.