Peptide testing and quality
Every WholesalePeptide.us research peptide lot is tested by an independent third-party laboratory using RP-HPLC (UV 214/220 nm) and LC-MS identity. Lots go to one of 5 laboratories: Freedom Diagnostics, Mistral Diagnostics, Vanguard Laboratory, Amino Metrics and Accumarks; the certificate names the lab that tested that lot. Lots below 99% purity are not released. Each lot's Certificate of Analysis is published in the COA library under the same lot code that is printed on the vial, so the document and the vial can be matched before and after you order. A lot-specific Certificate of Analysis is published before the lot ships.
What we test and how
| Check | Method | What it establishes |
|---|---|---|
| Purity | RP-HPLC, UV detection, full chromatogram published | Main-peak share of the peptide fraction; floor 99% |
| Identity | LC-MS, observed vs theoretical mass | That the molecule matches the intended sequence |
| Lot traceability | Lot code on vial, packing list and certificate | That the report belongs to the vial in your hand |
| Independence | Tested by an independent third-party laboratory | The lab is not the seller |
Our testing laboratories
Lots are sent to independent third-party laboratories: Freedom Diagnostics, Mistral Diagnostics, Vanguard Laboratory, Amino Metrics and Accumarks. The certificate for each lot names the laboratory that tested it, with a report number and the test date, so you can contact that laboratory directly to confirm the result. Every certificate is in the COA library.
How lots are released
- The finished, lyophilized lot is sealed and assigned a lot code.
- A sample goes to the independent lab under that lot code.
- The lot is released only if purity and identity results are within specification.
- The report is posted as a lot page in the COA library and attached to the order.
Read the evidence yourself
- How to read a peptide COA: line-by-line walkthrough.
- How third-party peptide testing works: what independence does and does not prove.
- HPLC vs mass spectrometry: purity and identity are different questions.
- Purity vs net peptide content: why vial weight is not peptide weight.
If your own test disagrees
Send us the lot code, your report and the lab's method. We compare it with ours, and if the difference is real we replace or credit the lot under our returns policy: Unopened kits in original tamper-evident packaging can be returned within 30 days for credit; opened or reconstituted material cannot be returned.
What this page does not claim
WholesalePeptide.us sells research chemicals. We do not describe them as pharmaceutical grade, and testing results describe laboratory quality only. For laboratory research use only. Not for human or veterinary use.
Next: browse the peptide catalog, see wholesale pricing, or open a wholesale account to have the COA attached to every invoice.
What is a peptide Certificate of Analysis?
A COA is the lab report for one production lot. Ours states the lot code, RP-HPLC purity with the chromatogram, LC-MS identity (observed vs. theoretical mass), net peptide content, the test date and the name of the lab (an independent third-party laboratory).
Is the COA for the exact vials I receive?
Yes. Every kit label carries a lot code, and A lot-specific Certificate of Analysis is published before the lot ships. Search this library by lot code to match a certificate to your kits.
How do I read a peptide COA?
Check the lot code matches your label, the HPLC purity and chromatogram, that the LC-MS mass matches the theoretical mass for the sequence, and the net peptide content. Our guide to reading a peptide COA walks through each field.
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For laboratory research use only. Not for human or veterinary use.