← Research Library · Published August 30, 2026
A Certificate of Analysis (COA) is a batch-specific laboratory document that reports identity and purity testing for a single production lot of a compound. It is not a certification, a licence, or a guarantee of anything beyond what was measured. Reading one well means knowing which fields matter and how to check them against the material in front of you.
The fields that matter
- Product name and identifier. The compound name, and ideally a CAS number, so there is no ambiguity about what was tested.
- Batch / lot number. The single most important field. It ties every result on the page to one production run — and it must match the number printed on your vial.
- Manufacture and/or test date. Tells you how current the analysis is.
- Purity by HPLC. Usually expressed as an area percentage, with the method, column, and gradient noted. A figure such as “≥99%” is a statement about the tested lot, not the brand.
- Identity by mass spectrometry. The observed mass compared against the theoretical mass for the intended peptide, within a stated tolerance.
- Appearance, and where relevant water/acetate content. Secondary checks that still tell you something about handling and formulation.
Reading an HPLC result
High-performance liquid chromatography separates the components of a sample as they pass through a column. The target compound appears as a main peak; impurities appear as smaller peaks at different retention times. Purity is reported as the area of the main peak divided by the total area of all peaks. Look for the method parameters on the COA — a purity number with no method behind it is hard to interpret and impossible to reproduce.
Reading a mass-spectrometry result
Mass spectrometry ionises the molecule and measures its mass-to-charge ratio. For a peptide you will typically see a protonated ion, or a series of multiply-charged ions, from which the molecular mass is calculated. Identity is confirmed when the observed mass falls within tolerance of the theoretical mass for that sequence. HPLC tells you how much of the sample is the target; mass spec tells you the target is actually the molecule you intended.
Matching the COA to your vial
Find the batch or lot number on your vial label and compare it, character for character, to the batch number on the COA. If they do not match, that COA does not describe your material — it belongs to a different production run. This one check catches the most common problem with COAs used as a marketing prop rather than a per-batch record.
Red flags
- No batch or lot number, or a batch number that never changes across obviously different orders.
- No method details for the HPLC or MS results.
- An image-only document with no traceable testing laboratory and no way to request the raw data.
- Purity claims stated as brand-wide absolutes (“100% pure”) rather than per-lot figures.
Verifying a Summit Labs COA
Where a Summit Labs product has a COA on file, it is linked on that product’s page and tied to a specific lot number. You can also search by batch or lot number on the COA lookup page and match the result to your vial. Products that do not have a COA linked yet say so directly on the page.
See also: HPLC and Mass Spectrometry: How Research Peptides Are Tested.
FAQ
Does a Certificate of Analysis guarantee purity?
No. A COA reports what one specific batch was tested for on one specific date. It is evidence of testing, not a guarantee, and it only describes the lot named on it.
What is the difference between HPLC purity and mass-spec identity?
HPLC estimates how much of the sample is the target compound versus impurities. Mass spectrometry confirms the molecule’s measured mass matches the intended peptide. A complete COA reports both.
For Research Use Only. All compounds sold by Summit Labs are intended solely for in vitro research and laboratory use. Not for human or veterinary consumption. Must be handled by qualified researchers in compliance with all applicable regulations.