Free tool
Free peptide COA checker: test any certificate's lot, lab, purity and mass
By Vitality Chems · Published · updated · vendor-authored explanatory note
Short answer
This free checker compares the fields of any peptide certificate of analysis against basic checks: the lot matches the vial, a lab is named and can confirm the report, the date is plausible, purity states its method and has a trace, and the observed mass matches the compound's PubChem molecular weight. It runs in your browser and sends nothing.
Catalog materials discussed on this page
COA checker
Type the fields from any peptide certificate of analysis. Everything runs in your browser; nothing is sent or saved.
3 problems, 5 items to check.
- ProblemLot number on the report
No lot or batch number entered for the report. A report without a lot number cannot be tied to any vial.
- ProblemIssuing laboratory
No laboratory named. An unnamed lab cannot be contacted to confirm the report.
- CheckLab confirmation
Not checked yet. This is the single strongest check: confirm the report ID with the issuing lab.
- CheckReport date
No report date entered.
- ProblemPurity result
No purity figure entered.
- CheckChromatogram or peak table
No chromatogram or peak table. A purity number without a trace cannot be checked.
- CheckIdentity by mass
No observed mass or m/z entered. Without a mass result, the report does not show what molecule was tested.
- CheckMeasured quantity
No measured mg per vial entered. A label claim repeated on a report is not a measurement.
How the mass check works
Enter a neutral mass, or an m/z value with its charge state z. The checker converts m/z to neutral mass as (m/z × z) − z × 1.007276 and compares it with PubChem's computed average molecular weight.
Within the larger of 1 Da or 0.05% counts as a match. Up to 0.2% is flagged as close, which often means the report used monoisotopic mass, a salt form or an adduct. Anything further is flagged as a mismatch.
What it cannot do
It cannot tell whether a PDF was edited. Only the issuing laboratory can confirm a report, which is why lab confirmation is one of the checks.
Related on Vitality Chems
- How to verify a peptide COA — confirm the report with the lab.
- Verify a lot — open our published report for your vial.
- COA testing standards compared — what each test proves.
- Expected m/z calculator — charge-state values for any mass.
- Retatrutide — lots with published HPLC and LC-MS reports.
- Tesamorelin — published lot report with LC-MS.
Frequently asked
Is the COA checker free?
Yes. It runs in your browser, needs no account, and sends nothing to us.
Which compounds have reference masses?
Compounds whose PubChem CAS number matches our catalog CAS number. For anything else, enter the reference molecular weight yourself.
Why is my mass flagged as close?
Reports sometimes give monoisotopic mass, a salt form, or an adduct such as sodium. Check which mass the report states before drawing conclusions.
References
- PubChem (National Library of Medicine)Reference molecular weights.
- NIST: CODATA proton massProton mass used for the m/z conversion.
