How to Read a Certificate of Analysis
What the numbers on a lab report mean, and the checks to run before you trust one.
A certificate of analysis (COA) links one batch of product to one set of lab results. It takes a few minutes to read once you know where to look. This guide covers the five checks we recommend for every batch.
Match the batch number
Find the batch number on your vial label and on the report. They must be identical. If they are not, the report describes a different batch and tells you nothing about the product you received. You can look up the report for your batch in our COA library.
Check the testing lab and date
A trustworthy report names the lab that ran the test and the date of testing. A report with no lab name, or a date long before the batch was made, should be treated with caution.
Look at the method and the purity figure
Purity is normally reported as a percentage from HPLC (high-performance liquid chromatography). The report should state the method used, not only the number. A purity percentage with no method listed cannot be checked.
Confirm the identity with mass data
Mass spectrometry (MS) confirms that the compound has the expected molecular weight. The measured value should sit very close to the theoretical value for that compound. This is what shows that the product is what the label says it is.
Keep a copy with your batch
Save the report alongside your batch number and purchase record. If you ever need to compare batches, or confirm which lot you used, you will have it in one place.
Quick checklist
- Batch number matches the vial label
- Testing lab named, with a test date
- Method stated (for example HPLC)
- Purity result shown as a percentage
- Mass data matches the expected molecular weight
All products are sold for laboratory research use only. They are not for human or animal consumption.