A certificate of analysis, usually called a COA, is the supplier’s record of what one batch actually tested at. It is the document that turns a grade on a website into a number for your consignment.
The short answer. A useful certificate of analysis names the product and the batch, gives the date, lists each parameter with the specification limit beside the result, and is signed by the person responsible for it. If a result has no limit beside it, or the batch number does not match the bags, ask before you accept the consignment.
| Item | Why it matters |
|---|---|
| Product name and grade | Confirms the certificate is for what you ordered, not a similar product. |
| Batch or lot number | Ties the certificate to the bags in front of you. It should match the bag marking. |
| Date of manufacture or test | Shows the certificate belongs to this batch and not an old one. |
| Each parameter tested | Tells you what was actually checked, which may be more or less than your specification. |
| Specification limit beside each result | A result alone cannot be judged. The limit tells you whether it passed. |
| Test method | Two laboratories can report different figures for the same sample if their methods differ. |
| Name and signature of the person responsible | Makes someone accountable for the figures. |
Put your specification and the certificate side by side. For each parameter you need, find the result and confirm it is inside your limit, not only inside the supplier’s. Then check the parameters you need that the certificate does not list. A parameter that was not tested has not passed; it is simply unknown.
Watch one thing closely: whether a figure is the content of the whole compound or of one element in it. ‘99% min’ for a compound and ‘33% Zn’ for an element are different kinds of number. Our page on how to read a Taskon product page explains the difference.
A batch certificate of analysis travels with every Taskon consignment. If you need particular parameters reported, send your specification with the enquiry, and we will tell you before you order what the certificate for your batch will cover.
For a first order, many buyers have an independent laboratory test a sample on arrival and compare the result with the certificate. It is a sensible step, and it costs far less than a production problem. Ask the laboratory to use a method that matches your specification, so the two figures can be compared fairly.
Buying more than one product? Send the full list and we will quote it as one consignment.
Send us the product, the quantity and where it is going.