Research
How to read a Certificate of Analysis
A Certificate of Analysis should be treated as analytical documentation, not a marketing claim. The first question is not “what is the purity percentage?” It is “what was tested, and can this report be connected to the material in front of me?”
Start with product identity. Confirm that the compound or research material named on the COA matches the product being evaluated. Next, check the lot number or sample identifier. A report tied to a different lot may not describe the specific material you received.
Then review the testing laboratory, test date, and analytical method. These details provide context for the reported results. If the report includes HPLC data, look beyond the headline percentage and review the chromatogram and method information where available. If identity testing such as mass spectrometry is included, confirm what the test was designed to establish.
The most useful COAs should make it possible to answer several basic questions:
- What material was tested?
- Which lot or sample was tested?
- Who performed the analysis?
- When was it tested?
- Which analytical method was used?
- What did that method actually measure?
- Do the reported results match the claims being made about the material?
A COA should also be read for its limits. One test does not automatically establish every characteristic of a research material. For example, a chromatographic purity result does not by itself prove identity, concentration, sterility, or suitability for a particular experiment unless those characteristics were separately evaluated.
Before beginning research, compare the lot information on the product with the report available in the COA database. If the product, lot, or analytical documentation does not match, contact support before relying on the report.
Educational content is for informational purposes and does not replace laboratory protocols, institutional requirements, manufacturer instructions, or professional scientific judgment. Products sold by USA Peptide Depot are intended for laboratory and research use only and are not intended for human or veterinary use.