What is a Certificate of Analysis?
A Certificate of Analysis (COA) is the primary document accompanying a research peptide that reports its measured purity and confirms its identity. For researchers, the COA is the key piece of documentation for evaluating whether a peptide meets the standard required for reliable experimental work. This guide explains what the main numbers on a COA actually mean.
This article is intended as a scientific overview for laboratory researchers. All compounds discussed are sold strictly for in-vitro research and are not for human consumption.
HPLC Purity Percentage
The most prominent number on most COAs is the HPLC purity percentage — for example, 99.0%. HPLC (High-Performance Liquid Chromatography) separates the components of a sample, and the purity percentage reflects how much of the sample is the target peptide versus other substances. A higher percentage indicates fewer impurities. For research use, high purity reduces the chance that contaminants affect experimental results. See our overview of how HPLC and mass spec work for the underlying methods.
Mass Spectrometry (Identity Confirmation)
Alongside purity, a COA typically reports mass spectrometry results. This confirms the peptide's identity by measuring its molecular mass and comparing it to the expected value for the target compound. Where HPLC answers "how pure is it," mass spec answers "is it actually the right molecule." Both together give a fuller picture than either alone.
What Else to Look For
A thorough COA may also include the sequence, molecular formula, net peptide content, and the testing date or batch number. Batch-specific documentation is important — a COA should correspond to the actual lot you receive, not a generic sample. Independent or third-party testing adds further confidence that the numbers are not self-reported without verification.
Why This Matters for Research
Because experimental reliability depends on knowing exactly what is in the vial, the COA is central to good research practice. Purity and identity documentation let researchers account for what they are actually working with. This is why reputable research suppliers provide batch-specific COAs.
COAs at Prime Peptide Solutions
We provide Certificates of Analysis for every batch, available on our COA page. Our research peptides are third-party tested for purity. Browse the catalog on our products page.
Sold strictly for in-vitro laboratory research. Not for human or animal consumption. This material has not been evaluated by the FDA.