Reading peptide documentation: identity, purity, content and COA

Understand what the test answers

Useful documentation starts with a match: product, variant, batch and version must refer to the correct material. Before comparing percentages, determine what was measured. Identity, chromatographic purity, assay, water and counterions address different questions; a single number cannot summarize them all.

A chromatogram shows an analytical response under defined conditions. Retention time, integration, method and detector all affect interpretation. A main peak does not automatically make every other component detectable or reveal the vial's complete actual content.

Complementary techniques

HPLC and related methods separate components under chromatographic conditions. Mass spectrometry provides another perspective on observed species and masses. Combined methods can strengthen an assessment of identity and impurities, but suitability depends on the method, sample and defined criteria.

ICH Q2(R2), available through the FDA, addresses validation of analytical procedures. This differs from recognizing a logo or acronym in a PDF: request enough information to understand the purpose and suitability of the procedure used.

A COA is not a universal seal

A certificate of analysis should be associated with its batch and issuer. Check the title, identification, version, dates, tests, results and criteria. Where possible, compare with the original document and confirm provenance through the registered channel. Finding an identifier on a website establishes that a record exists; it does not independently authenticate a physical package.

Sterility and endotoxins

FDA guidance separately addresses pyrogen/endotoxin testing and controls related to sterility. A chromatographic-purity result does not replace those tests. High purity alone does not establish suitability for human use.

Storage and release

Storage and transport conditions should come from the record applicable to the material. Do not extrapolate one sequence's stability to all others or assume that a cold-chain service was contracted. When requesting documents, describe the laboratory purpose and evidence needed so the team can confirm availability and scope before quotation.