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How to Read a Peptide Certificate of Analysis

A line-by-line walkthrough of a peptide COA: lot number, HPLC chromatogram, mass spec, endotoxin, moisture, and the three things to check before accepting a research shipment.

A Certificate of Analysis (COA) is the single most important document shipping with a peptide reference standard. Here is how to read one properly — and the specific red flags that should trigger a lot rejection.

What a Real COA Contains

A complete research-grade peptide COA has ten elements:

  1. Product name (e.g., BPC-157) and CAS number (137525-51-0)
  2. Molecular formula and weight (C62H98N16O22; 1419.54 g/mol)
  3. Batch / lot number — specific to this production run
  4. Manufacture date + expiration / retest date
  5. HPLC chromatogram with method disclosed (column, gradient, detector)
  6. Mass spec result (observed vs theoretical)
  7. Endotoxin result by LAL (EU/mg)
  8. Moisture result by Karl Fischer (%)
  9. Counterion content (TFA or acetate, as % of net mass)
  10. Signature + reviewer — release authority

If any of items 5–9 are missing or replaced with “NMT” / “as per specification” language with no raw data, the document is a spec sheet, not a COA.

The Three Red Flags

1. Generic HPLC method

A credible COA shows: column packing, dimensions, mobile-phase composition, gradient program, flow rate, detector wavelength, injection volume. If it says only “HPLC: ≥ 99%” with no method disclosure, assume the purity number is not defensible.

2. Missing mass-spec confirmation

HPLC purity is about homogeneity; mass spec is about molecular identity. A COA with only HPLC is incomplete. Look for “ESI-MS observed: [x] Da; theoretical: [y] Da” with a delta under 0.5 Da.

3. Stale / re-used lot numbers

If a supplier ships two separate orders with the same lot number six months apart, either the material is from the same original batch (acceptable, but the retest date should reflect it) or the supplier is recycling documentation. Ask to see the current retest result.

How BioFusion Handles This

Every BioFusion Aminos peptide lot publishes a full COA in the public COA library, pre-purchase. Each lot includes: HPLC chromatogram image with method, MS observation vs theoretical, LAL endotoxin, Karl Fischer moisture, and the signed release line. Our Batch Transparency ledger adds the synthesis date, purification fraction record, and an independent-review archive.

A Worked Example Read

Sample COA line items for a BioFusion BPC-157 lot:

  • HPLC purity: 99.6% (C18, 150 × 4.6 mm, 5%→65% ACN/TFA over 30 min, 220 nm)
  • Mass spec: observed 1419.54 Da (ESI+), theoretical 1419.54 Da, Δ 0.00 Da
  • Endotoxin: < 0.10 EU/mg (LAL gel-clot)
  • Moisture: 3.2% (Karl Fischer)
  • TFA counterion: 12% (by ion chromatography)

A lab can take that COA, trace the lot from purchase to end-of-use, and if questions arise, the manufacturer has the release record.

What a Bad COA Looks Like

Common bad-COA patterns (seen across the consumer-peptide industry):

  • “Purity: ≥ 99%” with no chromatogram image.
  • “Mass spec: passes” with no observed mass.
  • A logo and product name but no lot number.
  • The same PDF for every SKU the supplier sells (a generic template).

If any of these are present, treat the material as un-validated.

Related Reading

Laboratory research use only.