A Certificate of Analysis is only useful if you know how to read it. This guide explains the key data points in a research peptide COA — HPLC purity, mass spectrum, Janoshik verification — and what red flags to look for when evaluating a vendor’s testing claims.
What a Research Peptide COA Should Include
A genuine, research-grade peptide Certificate of Analysis contains specific analytical data, not just summary numbers. Here is what every COA should include and what each element tells you:
1. HPLC Chromatogram — Not Just a Number
High-performance liquid chromatography (HPLC) separates peptide components by their interaction with a stationary phase under a mobile phase gradient. The output is a chromatogram — a graph of UV absorbance (typically at 220nm) over time. Peptide peaks appear as peaks on this graph; purity is calculated as the target peptide peak area as a percentage of total peak area.
What to look for: A genuine HPLC COA shows the actual chromatogram — not just the final purity percentage. The chromatogram shows you the peak shape (symmetrical peaks indicate good synthesis), the location of the target peak relative to the gradient, and the relative size of any impurity peaks. A COA that shows only “purity: 99.2%” without a chromatogram is providing a conclusion without evidence.
Red flag: A purity number without a chromatogram. Chromatograms can be fabricated, but their absence is a clear quality signal — genuine analytical labs routinely include them.
2. Mass Spectrometry — Identity, Not Just Purity
Mass spectrometry (MS) measures the mass-to-charge ratio (m/z) of ionised molecules, providing the molecular weight of the compound. For peptides, this confirms that the dominant HPLC peak is actually the target peptide — a peptide could be 99% pure but be the wrong sequence if a synthesis error occurred.
What to look for: The observed molecular weight (M+H)+ or multiply-charged ions should match the theoretical molecular weight of the target peptide within instrumental precision (typically ±0.1 Da for small peptides, ±1–5 Da for larger ones). For example, BPC-157 (MW 1419.5 g/mol) should show a dominant MS peak at approximately m/z 1420.5 for the [M+H]+ ion.
Red flag: COAs with HPLC data but no MS data. Purity analysis without identity confirmation is incomplete.
3. Batch Number and Compound Identity
The COA should clearly identify the specific compound by name and/or CAS number, and include a unique batch or lot number traceable to that specific production run. Generic COAs without batch numbers may be reused across multiple production runs — or fabricated entirely.
4. Janoshik Verification Reference
Janoshik (verify.janoshik.com) is the independent verification standard in the research peptide community. Vendors who submit batch samples to Janoshik receive a publicly searchable verification record. The Janoshik reference number should appear on the COA, allowing any researcher to confirm the test was conducted independently and the results are authentic.
Why this matters: A COA is a document the vendor produces. Without third-party verification, you are trusting the vendor to accurately report their own test results. Janoshik verification makes the results independently confirmable — the record exists on Janoshik’s servers and cannot be retroactively modified by the vendor.
Common COA Red Flags
QSC’s COA Standard
Every QSC research peptide batch includes: the full HPLC chromatogram with peak area integration, mass spectrometry molecular weight confirmation, batch number, compound identity, and a Janoshik verification reference number. COAs are published proactively on every product page — not provided on request.
To verify any QSC batch independently, go to verify.janoshik.com and enter the batch reference from the product page COA.
Further Reading
QSC Testing Standards — Full Process ·
What Is Janoshik? ·
Peptide Supplier Buying Guide