How to Read a Certificate of Analysis (COA)

How to Read a Certificate of Analysis (COA)

For in vitro laboratory research use only. This guide is for information only. Peptix makes no claims about the effects of any material it sells.

A Certificate of Analysis (COA) is the report an analytical laboratory issues after testing a sample from a specific lot. This guide walks through the fields on the certificates Peptix posts for the lots listed on our COA page, which are issued by Freedom Diagnostics, an independent laboratory.

The header: who tested what, and when

• Client, accession number and search code: identify the submission at the testing lab.
• Received / Reported: when the lab received the sample and when it issued the report.
• Lot: the batch the sample came from. A certificate applies only to that lot.

The results

• Purity (HPLC-UV): the share of the main peak in the chromatogram measured by high-performance liquid chromatography with UV detection, reported as a percentage.
• Identity (LC-MS): liquid chromatography with mass spectrometry, used to check that the measured mass matches the expected compound. The result line names what was identified.
• Net content: the amount the lab measured in the tested vial, as printed on the certificate. It can differ from the labeled amount stated on the product label.
• Appearance: how the sample looked when received, for example “White Lyophilized Powder.”

The traces

• Chromatogram and mass spectrum (where printed): the raw traces behind the results. In the chromatogram, the largest peak is the main component used for the purity calculation; smaller peaks are other components detected by the method. Where a mass spectrum is printed, it shows the measured masses used for the identity check.

What a COA does and doesn’t tell you

A certificate reports results for the sample tested. It is not a guarantee for other lots. That’s why the lot number matters: always compare the lot on your vial with the lot printed on the certificate.

How to match your vial’s lot number to its COA

1. Find the lot number printed on your vial label or box (for example, BC-20260521-01).
2. Find the same lot ID in the table on our COA page.
3. Open the certificate and check that the lot number printed on it is identical, character for character.
4. If the lot on your vial isn’t listed, or doesn’t match, contact Peptix support with your order number and the lot number before using the material.

Related

• Certificates of Analysis: the lots listed on our COA page, with their certificates
• What “HPLC purity” means
• Browse research peptides

All Peptix products are sold for in vitro laboratory research use only. Not for human or animal use.