Certificate of analysis fields: what each one means
Last reviewed: 2026-10-10 · Sable Peptides research team
A peptide certificate of analysis records the tests performed on one batch. Identity is shown by mass spectrometry, purity by HPLC peak area, and net peptide content by mass balance or amino-acid analysis; these are separate measurements.
| Field | What it tells you | Typical method | What a complete entry shows | What a weak entry lacks |
|---|---|---|---|---|
| Lot/batch number | links the report to one batch | – | the same code as the vial label | no lot, or a lot that differs from the vial |
| Laboratory and report number | who tested it | – | named lab with independent contact details, report ID on every page | unnamed lab |
| Test date | when it was tested | – | a date consistent with the batch | no date |
| Identity | that it is the named peptide | ESI or MALDI mass spectrometry | observed vs theoretical mass, within tolerance | “confirmed” with no numbers |
| Purity | share of UV-absorbing material in the main peak | RP-HPLC, area %, 214/220 nm | method, wavelength and chromatogram | a bare % with no method |
| Chromatogram | the raw evidence for purity | HPLC trace | trace with peak table | missing |
| Net peptide content | how much of the powder is peptide | amino-acid analysis or mass balance | % stated | absent |
| Counter-ion | the salt form (TFA or acetate) | ion chromatography or NMR | identified and quantified | not disclosed |
| Water content | residual water | Karl Fischer | % stated | absent |
| Appearance | physical form | visual | e.g. white lyophilised powder | absent |
A CoA for every lot; each vial carries a printed lot number that matches it. Ask with the lot number and we send it. See lot numbers and CoA.
Research use only. Not for human consumption. No health claims.