Identity: which compound?
Identity testing asks whether the submitted material matches the named compound. Read the laboratory’s stated method and result. Do not infer an identity test solely because a purity value appears on the report.
Methods and certificate formats differ. An instrument name mentioned elsewhere on a website is not evidence that a particular test was performed on your sample.
Purity: what does the percentage describe?
Chromatographic purity expresses the target’s share of the integrated signal under the stated analytical method. Its meaning depends on the method and the report’s definition.
It is not a direct statement of how many milligrams of peptide are in a vial. It also does not stand in for tests that look for particular contaminants.
Quantity: how much peptide was measured?
A content or assay result reports the measured amount, with its units. Net peptide content and total sample weight are different things, so use the term the laboratory actually reports.
Fill accuracy compares measured peptide content with the labelled amount. It is a different percentage from chromatographic purity. Check the certificate’s own specification before interpreting it.
Read the three together
Start with the sample and lot identifiers, then examine each result independently. Keep the method, unit and specification beside the value.
If one of these measurements is missing, leave that question open. Another favourable result cannot supply an analysis that was never performed.
References & further reading
Vanguard Laboratory · Peptide testing methods and scope (opens a new tab)Pepline · Understanding the measurementsExternal educational references do not imply a Pepline laboratory affiliation. General information for laboratory research; not guidance for human or veterinary use.