Compound name and reference number

The top of the COA identifies the compound by its standard name (e.g. BPC-157) and often a CAS or internal reference number. Cross-check this against your order — suppliers sometimes ship the wrong vial. A mismatch here means stop, not proceed.

Batch (lot) number

Every batch has a unique identifier. This is what links your specific vial to the analytical work done on it. If the COA you receive lists a different batch number than what is printed on your vial, you are looking at the wrong paperwork. Ask for the right one.

Purity (HPLC)

The most scrutinised number on the page. Look for:

  • A direct measured value (e.g. 98.6%), not "≥ 98%".
  • The analytical method reference (C18 column, UV detection at X nm, gradient program).
  • An attached chromatogram ideally — the visual HPLC trace supporting the number.

A number without a method means you cannot compare it to other batches or other suppliers on equal terms. A good COA provides both.

Identity: mass spectrometry

Purity tells you how much of a single molecule is in the vial. Mass spec tells you that molecule is actually what you ordered. A 99% pure compound of the wrong peptide is still useless research material.

Look for the theoretical molecular weight (calculated from the sequence) versus the observed mass — they should match. Fragmentation patterns provide further structural confirmation.

Water content (Karl Fischer)

Lyophilized peptides retain some residual water. Typical values are 5 to 10%. This affects your effective mass: a 5 mg vial with 10% water contains roughly 4.5 mg of peptide plus 0.5 mg of water. For stock-concentration calculations, correct for water where the number is meaningful to your protocol.

Acetate content (TFA/acetate salt)

Many synthetic peptides are supplied as the acetate or trifluoroacetate salt. The COA will list the salt form and percentage. Like water content, this reduces your effective peptide mass and should be factored into any precise concentration work.

Red flags

Ask the supplier — or move on — if any of these are missing or unusual:

  • No batch number, or a batch number that does not match the vial label.
  • Purity expressed as "≥ 98%" with no measured value and no chromatogram.
  • No mass spec identity data at all.
  • A COA that looks like a template with values simply typed in rather than an exported lab report.
  • Old date of analysis on a peptide with known stability limits.

Getting the right COA

Some suppliers publish COAs publicly; others issue them on request with your order reference. Both are fine — what matters is that the COA you receive is the one matching your batch, not a generic example.

TogoPeptide issues COAs on request with the order reference. See the Lab Reports page for the process.