How to read a peptide certificate of analysis
A polished PDF is not evidence by itself. Traceability comes from fields that connect the report to a sample, a method, a date and an issuing laboratory.
Start with the lot number
The lot is the link between the certificate and the label. If it is absent or different, the measurements cannot be tied to the item in front of you.
Require a method beside each result
Purity and identity answer different questions. HPLC can separate and quantify components; mass spectrometry can support an identity claim by measuring mass. A bare percentage omits how it was measured.
Verify the report at its source
Use the laboratory’s own verification portal or contact details obtained independently, not a link printed only by the seller. Match the report identifier, lot and date. If the laboratory confirms only that a report number exists, ask whether the compound, sample identifier and reported values are also identical.
Check the analysis date and chain of custody
A readable analysis date helps establish when the sample was measured, but it does not show how the material was stored afterward. Look for the laboratory’s receipt date, analysis date and report date. Large unexplained gaps, a report that predates the labelled lot, or a document reused long after testing are reasons to treat the linkage as incomplete.
Read beyond the headline purity number
A main-peak percentage does not identify every remaining component. A useful report states the method, units, integration approach and relevant impurity results or limitations. It should also distinguish the sample as received from any calculation on a dry or corrected basis. Peptely flags omissions; it does not invent a contaminant result that the laboratory did not report.
Peptide questions
Can a genuine certificate be reused?
Yes. A genuine report for one lot can be circulated with another. That is why the lot match matters.
Does 99% purity prove identity?
No. Purity and identity are separate measurements and should not be treated as interchangeable.
Does an ISO/IEC 17025 logo prove this test is accredited?
No. Confirm the issuing legal entity, site and method against the accreditor’s published scope.
What if the laboratory is absent from Peptely’s registry?
Absence is a verification gap, not an accusation. Check the laboratory and accreditation body directly and send Peptely the primary record for review.
Does a passing document check mean the vial is safe?
No. A document check cannot test the vial, establish chain of custody or decide whether a compound is appropriate for a person.
Sources and further reading
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