How to Read
a COA
We break down a real Certificate of Analysis section by section — so you can tell at a glance what the sample is, how it was tested, and whether the numbers hold up.
Educational content only. A COA is a snapshot of lab testing for one specific batch — not a stamp of safety or a legal clearance. Treat it as one input in your wider sourcing checks, never the whole story.
An Annotated COA, End to End
Below is a full Certificate of Analysis with every major section called out. Use it as a map — each numbered callout matches a section further down this page.
1. Sample Information
The header block identifies exactly what was tested and ties the report to a single production run. This is what makes a COA traceable.
Product & Form
The compound name and its physical form, such as lyophilized powder.
Batch / Lot Number
The link between this report and the exact batch. A new batch should ship with a fresh COA.
Molecular Formula & CAS Number
The chemical fingerprint. Should match published reference values for the compound.
Labeled Quantity
How much material the vial is meant to contain — sanity-check this against the net content result.
Cap & Crimp Color
Small physical identifiers that help you confirm the vial in hand matches the report.
2. Test Results
This table compares each measurement against a reference standard. Every row should show a result that meets or beats the stated spec.
Purity
The headline number, usually from HPLC. A reference of >98% with a result like 99.4% means the target compound dominates the sample.
Net Content
The measured amount of active compound, checked against the labeled quantity.
Identity Confirmation (LC-MS)
Mass spectrometry confirming the molecule is what the label claims.
Endotoxin Safety Screen
Checks bacterial endotoxin levels against a safe threshold (e.g. ≤0.5 EU/mL).
Fentanyl Presence Analysis
Screens for fentanyl contamination — you want to see 'Not Detected'.
Microbial Sterility Screen
Confirms no microbial growth in the sample.
3. Heavy Metal Screening
A dedicated table confirms that toxic heavy metals sit below safe limits. Each analyte should read as a low "less than" value with a passing status.
- Arsenic (As)
- Cadmium (Cd)
- Lead (Pb)
- Mercury (Hg)
Results are typically reported as a threshold (for example < 0.15) rather than an exact figure — the point is simply that contamination stays under the acceptable ceiling.
4. Chromatogram (HPLC)
The chromatogram is the visual proof behind the purity number. HPLC separates the sample into its components, and each one shows up as a peak.
Reading the chart: one tall, dominant peak labeled with the compound name is your target. A near-flat baseline elsewhere means few impurities.
5. Signature & Verification
The footer is where accountability lives. A real COA is signed off and offers a way to confirm it's genuine.
Lab Director Signature
A named person taking responsibility for the analysis — not just an anonymous stamp.
Report Number
A unique identifier you can quote when checking the certificate with the lab.
QR Code & Access Code
A direct route to verify the report on the lab's own site. Always confirm it resolves.
Quick reference checklist
Do the product name, molecular formula, and CAS number match what you ordered?
Does the batch/lot number on the COA match the vial in hand?
Is purity clearly stated, with a result that meets the reference standard?
Did identity confirmation (LC-MS) return the correct compound?
Do endotoxin, fentanyl, and sterility screens all pass?
Are all heavy metals below their limits?
Does the chromatogram show one clean, dominant peak?
Is the report signed, numbered, and verifiable via QR or access code?