Start with the sample, not the headline number
A certificate of analysis is useful only when it is connected to the material being evaluated. Match the compound name, batch or lot number, sample identifier and report date. If the report describes a different batch, ask for the matching documentation rather than treating a familiar compound name as sufficient.
Separate the analytical questions
ICH Q2(R2) treats identity, assay, purity and impurities as distinct analytical purposes. A practical reading checklist is to ask what each result measures, which method produced it, and whether that method is appropriate to the stated question. A purity percentage alone does not answer every quality question.
Read the method and units
Locate the method identifier and the units next to each result. A percentage, a measured mass and an amount per vial describe different things. Ask whether the result is a measured value, a specification limit, or a statement such as pass. Request supporting analytical records where interpretation requires them.
Questions to send with a documentation request
- Does this report match the supplied lot?
- Which test supports identity, and which supports purity or assay?
- What method and reporting units were used?
- Can the issuing laboratory and report identifier be verified?
- Which properties were not tested?
What a COA does not establish
A document is evidence about the reported tests. Do not infer approval, clinical effectiveness, or an unreported property from its appearance. This checklist is an interpretation aid, not a claim that Peptides51 has independently tested a batch. For method-specific interpretation, consult the issuing laboratory.