How to read a peptide Certificate of Analysis

Start with the document match

Before reading a purity percentage or any other result, confirm which record is in front of you. The material or sample name, lot number, issuing laboratory, report date, and COA number should form one consistent record.

Compare those identifiers with the product or lot reference shown on the site. A document for a similarly named material or a different lot is not interchangeable with the record you intended to review.

• Material or sample name
• Lot or batch number
• Issuing laboratory or source
• Report date and COA number

Separate identity from purity

Identity and purity answer different analytical questions. An identity-related result addresses whether the measured material is consistent with the named sample under the stated method. A purity result describes the reported chromatographic composition under its stated method.

A high purity percentage does not independently establish identity. An identity result does not replace a purity measurement, content result, endotoxin field, heavy-metals field, or any other separate analysis.

Read the method with the result

A result should stay attached to the method printed beside it. RP-HPLC, MALDI-MS, HPLC quantitation, endotoxin methods, and elemental or heavy-metals methods measure different things. A method name alone is not a result, and a result without its method loses important context.

Chromatograms and spectra can provide supporting analytical detail, but they still belong to the named sample and lot. They should not be carried over to another record.

Treat every additional field separately

Some posted records include endotoxin, heavy-metals, pH, water-content, or other analytical fields. Read each only when it appears on the relevant COA, with the unit and method shown by the issuer.

Endotoxin reporting is not a sterility test. A heavy-metals result is not a complete contaminant screen. Neither field should be implied for a material or lot whose posted record does not show it.

Verify the public lab record

When a laboratory provides a public verification number, use it to open or search for the matching lab-hosted record. Compare the material, lot, date, and reported fields with the copy posted on the CellSyntax report page.

A matching public lab record confirms that the laboratory hosts a record with those identifiers. It should not be described as proof of packaging, delivery, chain of custody, or suitability for a particular use unless separate evidence establishes those points.

Know the document boundary

A COA is not use guidance, a medical claim, or a guarantee of suitability. It does not make one result universal across products, sizes, or future lots.

If an identifier, method, unit, or result is missing or unclear, leave the question unresolved. The narrow answer is more useful than filling a gap with marketing language.