A certificate of analysis (COA) is the single most important document a research peptide supplier can give you. It is also one of the easiest documents to read incorrectly — or to look at and skim past without actually understanding what it says. This is a walkthrough of how to read a Janoshik Analytical COA in particular, which is the most-trusted third-party testing house in the research peptide space, and which Bastion uses for every batch.
A Janoshik COA contains two main test results: HPLC for purity, and LC-MS for identity and mass accuracy. This article walks through what each test does, how to read the report, and what to flag if something looks off.
What HPLC tells you
High-Performance Liquid Chromatography (HPLC) is the standard purity test for peptides. The basic principle: a small amount of the sample is dissolved, pushed under high pressure through a column containing a stationary material that interacts with different molecules at different rates. Molecules exit the column at different times — their “retention times” — and a detector at the column’s output measures how much of each elutes at each time.
The output is a chromatogram: a graph with time on the x-axis and absorbance (a proxy for “how much of something is exiting right now”) on the y-axis. A pure peptide shows as a single tall peak at a specific retention time, with very little signal elsewhere.
What to look for on the HPLC chart:
- The main peak. Should be tall, narrow, and clearly above the baseline. This is the target peptide.
- Other peaks. Smaller peaks at other retention times indicate impurities — partial sequences, oxidation products, contaminants. Their height relative to the main peak indicates the contamination level.
- The purity number. Stated as a percentage (e.g., “99.2%”). This is the integral of the main peak as a fraction of the total integral across the chromatogram. The standard threshold for research-grade peptides is ≥98%; ≥99% is the published-research bar.
Worked example: BPC-157 batch COA
A typical Bastion BPC-157 batch HPLC report shows:
- Single main peak at approximately the expected retention time for the BPC-157 sequence (varies by column and method, typically 6-12 minutes on Janoshik’s standard protocol).
- Purity: ≥99% (the integrated peak area as a fraction of total area).
- No significant secondary peaks above approximately 0.5% of the main peak height.
That combination — single tall peak, ≥99% integrated purity, no significant secondaries — is what a “good” peptide looks like. If you see multiple peaks of similar height, that’s a peptide mixture, not a pure peptide. If the purity is below 95%, the sample has substantial contamination. If the main peak is shifted significantly from the expected retention time, that’s a flag — possibly a different peptide than advertised.
What LC-MS tells you
Liquid Chromatography Mass Spectrometry (LC-MS) adds identity confirmation to the purity measurement. The HPLC step separates molecules by retention time; the MS step measures their mass-to-charge ratio (m/z). The result tells you not only how much is in the sample but what its molecular mass is.
For a peptide, the expected mass is calculable from the sequence — each amino acid contributes a known mass, the peptide bonds release water, and the resulting molecular weight is the theoretical mass. The MS instrument measures the actual mass of the molecules exiting the column.
What to look for on the MS report:
- The measured mass. Should match the theoretical mass for the peptide sequence within a small tolerance — for high-resolution MS, typically within 0.01 Da. Janoshik reports the measured mass to four decimal places.
- The mass error. Often reported in ppm (parts per million). A mass error below 5 ppm is excellent; below 10 ppm is acceptable; above 20 ppm is a flag.
- The charge state. Peptides typically appear in multiple charge states (singly protonated, doubly protonated, etc.). The reported mass is the deconvoluted neutral mass — what the peptide weighs when uncharged.
Why mass accuracy matters
An HPLC purity number of 99% tells you that 99% of the sample mass is one molecule. It does not tell you that the one molecule is the one you expected.
A peptide that’s 99% pure but is a different peptide than advertised is still “99% pure” on the HPLC chart — the test can’t distinguish “the correct peptide” from “a different peptide of similar retention time.” LC-MS is what closes that gap: the mass measurement confirms the sequence.
For BPC-157, the theoretical monoisotopic mass is approximately 1418.7 Da. A Janoshik LC-MS report on a real BPC-157 batch should show a measured mass within roughly 0.05 Da of that — and any significant deviation is a serious flag, possibly indicating the wrong peptide entirely.
The Janoshik report layout
A Janoshik COA typically contains, on a single one or two-page document:
- Header. Sample identifier (batch number), date received, date tested, compound name as submitted.
- HPLC section. Method description (column, mobile phase, gradient), chromatogram image, integrated peak areas, calculated purity percentage.
- LC-MS section. Method description, mass spectrum image, theoretical mass, measured mass, mass error in ppm.
- Conclusion. A summary line stating purity and identity confirmation status.
- Signature / verification. Janoshik’s lab signature and a verification code that can be checked at janoshik.com.
That last point matters: Janoshik publishes a verification mechanism. A real Janoshik COA has a verification code that you can plug into their public verification page to confirm the report is authentic and was not fabricated. Any supplier that’s hiding the verification code or whose COAs don’t verify against Janoshik’s database is suspicious.
What to flag on a COA
Five things to check on any supplier-provided COA:
- The batch number on the COA matches the batch number on your vial. A COA that doesn’t have a batch number, or whose batch number doesn’t match what’s on the vial label, is uninformative. The point of a COA is that it ties to a specific batch.
- HPLC purity ≥98%. Below that, the sample contains meaningful impurities.
- Mass error below 10 ppm. Above that, the measured mass doesn’t confidently match the expected sequence.
- The verification code resolves. Check it against Janoshik’s verification page. A non-resolving code means the COA is fabricated or doctored.
- The test date is recent. A COA from 18 months ago doesn’t tell you the current batch is the same composition. Batches change; older COAs may not apply.
If any of these five fails, the supplier’s compliance posture is materially weaker than what the COA implies. The presence of a COA is not the same as the COA being good.
How Bastion handles per-batch COAs
Every order from Bastion includes a Match-Batch COA in the order completion email. The email contains:
- Each line item with its batch number explicitly shown
- A direct link to the Janoshik COA for that specific batch
- The verification code that resolves on Janoshik’s site
The Match-Batch COA is the differentiator: rather than publishing a generic “we test every batch” claim, the customer can see — on a per-order, per-line-item basis — exactly which batch shipped and the corresponding test report. The Lab Results page on the site also publishes a rolling index of current-stock batch COAs.
For researchers building a procurement workflow that survives audit, Match-Batch COAs are the practical bar. A supplier that ships a vial without telling you which batch it’s from — or that publishes a single COA from months ago for the whole catalog — is not actually third-party tested in any operationally useful sense.
For research use only. Bastion Peptides supplies compounds intended for laboratory and in-vitro research. Not for human or veterinary consumption.