Vendor-check guide · Research use only · Not for human or animal use · 18+
Coupons Peptides

Check 01

Reading a certificate of analysis

A certificate of analysis (CoA) is a test report for a product. It's only useful if it clearly belongs to the batch in front of you and comes from a lab you can identify. Here's what to look for, line by line.

What should be on it

Product nameMatches the product label exactly.
Lot or batch numberMatches the number on the packaging you received. A certificate with no lot number can't be tied to anything you bought.
Test dateA date for when the testing was done.
Testing labThe name, address and contact details of the lab that ran the tests, not only the seller's name.
Method for each resultEvery result names the test used to get it.
Results and limitsEach result has units and the limit it was checked against.
Sign-offWho reviewed or approved the report, and when.

What the methods tell you

A purity percentage on its own doesn't tell you which impurities were looked for. Researchers at the US Food and Drug Administration have reported that liquid chromatography with UV detection (HPLC-UV) may not be adequate to separate and measure all of the impurities that can occur in peptides, such as missing or extra amino acids, oxidation and deamidation. They showed that liquid chromatography combined with high-resolution mass spectrometry could identify and measure these impurities.[1]

So a certificate that gives only a purity number, with no identity test, tells you less than one that also names a mass-spectrometry result.

Checking the lab

Testing laboratories can be accredited to the international standard ISO/IEC 17025.[2] Accreditation is granted by accreditation bodies. In the US, one of these is NIST's National Voluntary Laboratory Accreditation Program (NVLAP), which publishes a directory of the labs it accredits.[3] The international ILAC agreement lists accreditation bodies around the world, and its signatory search often links to their databases of accredited labs.[2]

If a certificate says the lab is accredited, look the lab up with the accreditation body it names, and check that the accreditation's scope covers the kind of testing on the report. You can also contact the lab directly and ask whether it issued a report with that number.

Warning signs on a certificate

  • No lot number, or the same certificate shown for every batch.
  • No outside lab named, or a lab you can't find anywhere except the seller's own site.
  • Details that don't match the product page, such as a different product name, amount or batch.
  • A purity number with no method named.
  • Mismatched fonts, misaligned text or other signs the document has been edited.
  • A certificate that's only available after you've paid.

Sources

  1. Zeng K, Geerlof-Vidavisky I, Gucinski A, Jiang X, Boyne MT. Liquid chromatography-high resolution mass spectrometry for peptide drug quality control. AAPS Journal. 2015;17(3):643–651. Free full text (PubMed Central)
  2. ILAC. ILAC MRA and signatories.
  3. NIST. National Voluntary Laboratory Accreditation Program (NVLAP).