How to Read a Peptide Certificate of Analysis
HPLC, mass spectrometry and batch identity explained for laboratory documentation review.
Research use only. This guide explains laboratory documentation and is not medical advice or instructions for human use.
A Certificate of Analysis, usually called a COA, connects a product label to analytical results, methods and a traceable batch identity. A useful COA does more than show a purity number.
Start with the batch information
Compare the product name, batch or lot number and test date with the vial and order documentation. A result is meaningful only when it can be linked to the exact material in front of you.
What HPLC tells you
High-performance liquid chromatography separates components in a sample. The chromatogram shows peaks at different retention times, and the principal peak is commonly used to estimate chromatographic purity relative to other detected peaks.
Read the result in context. Check the method, detection wavelength, integration and whether the actual chromatogram is included. HPLC purity does not by itself prove molecular identity, sterility or suitability for a particular experiment.
Why mass spectrometry matters
Mass spectrometry supports identity testing by comparing observed molecular mass with the expected mass. HPLC and MS answer different questions: chromatography describes sample composition, while mass spectrometry helps confirm molecular identity.
Other fields worth checking
- Appearance and description of the supplied material.
- Quantity or declared net content.
- Storage and handling guidance.
- The laboratory responsible for analysis.
- Acceptance criteria used for assessment.
Common red flags
Be cautious when a document has no lot number, no test date, unreadable graphs, inconsistent product names or only a typed purity figure without supporting data.
A simple review workflow
- Match the batch number on vial and document.
- Confirm product name and declared content.
- Review HPLC result and chromatogram.
- Check the MS result against expected mass.
- Archive the document with experiment notes.
Peptidech products are supplied strictly for laboratory research and are not intended for human consumption.