A CoA answers one question: did this batch, when tested, meet these limits? For industrial chemicals there is no single legal format; content follows the specification and the supply contract. The most detailed official guidance on CoA content is pharmaceutical GMP for active ingredients (ICH Q7), and it is a sound model for any chemical [1].
Under ICH Q7, a CoA should give the name of the material and, where appropriate, its grade, the batch number and the date of release, plus the expiry or retest date where one applies (section 11.41). It should list each test with its acceptance limits and the numerical results (11.42), and be dated and signed by authorised quality personnel, showing the original manufacturer's name, address and telephone number (11.43) [1].
A CoA describes quality at the time of testing. It is not a safety data sheet, and it says nothing about where the material legally originates. Regulated users do not take it on trust: U.S. drug GMP rules accept a supplier's report of analysis only if the user runs at least one specific identity test and checks the reliability of the supplier's results at appropriate intervals [2].
Why it matters for surplus chemicals
Surplus lots often change hands more than once, and the certificate can drift away from the drums it describes. ICH Q7 addresses this: when repackers, agents or brokers issue a new certificate, it should name the laboratory that performed the analysis, refer to the original manufacturer and the original batch certificate, and attach a copy of it (11.44). Traders should also give buyers the original manufacturer's name and the batch numbers supplied (17.61) [1].
Where the original CoA is old, buyers commonly ask for a fresh analysis of a representative sample, because some properties change in storage. The CoA is one of the documents a buyer needs before it can qualify a surplus batch.
What to check
- The batch number on the CoA matches the container labels and the quantity offered.
- Results are numerical, with acceptance limits and test methods, not just "conforms".
- The date of analysis or release and any retest or expiry date are stated.
- The issuer is identified: the original manufacturer, or a named laboratory referring to the original certificate.
- The parameters critical to your application are covered; if not, request additional tests.
- Older stock has a recent result on a representative sample, and you plan an identity check on receipt.
Frequently asked questions
Is a certificate of analysis the same as a certificate of conformance?
No. A certificate of conformance states that a product meets a specification. A CoA reports the actual results for a specific batch, so the buyer can see how close each parameter is to its limit.
How old can a CoA be?
There is no general legal limit. What matters is the retest or expiry date and the storage history since testing. A retest date is the date when a material should be re-examined to ensure it is still suitable for use [1], so a CoA for a batch past that date should be backed by new results.
Sources
- ICH Q7 Good Manufacturing Practice Guidance for Active Pharmaceutical Ingredients, Revision 1 (FDA edition, September 2016)
- 21 CFR 211.84: Testing and approval or rejection of components, drug product containers, and closures
General information, not legal advice. Rules differ by country and by the facts of each lot.