What an HPLC certificate of analysis actually shows you
Every Aevum lot is third-party HPLC and mass-spec tested before release. The certificate is the document that proves it. Here is how to read one: what the peaks mean, what purity figures are calculated, and why mass spectrometry is the second leg of the test.
A Certificate of Analysis (COA) is the document a testing lab issues when a sample of a finished product is verified for identity and purity. For research-grade peptides, the COA is the difference between a label that claims 98% purity and evidence that 98% purity is what the customer received. We commission HPLC and mass-spec testing on every lot before release; the COA travels with the cartridge and is also published online by lot number. This is what is on it.
The HPLC chromatogram
The largest visual on a typical peptide COA is the High-Performance Liquid Chromatography (HPLC) chromatogram — a graph with retention time on the x-axis and detector signal on the y-axis. The sample is dissolved, injected into a column packed with a stationary phase, and pushed through with a moving solvent. Different molecules bind to the stationary phase with different affinities, so they exit (elute) at different times. A detector at the column exit records the signal — usually UV absorbance at 214 or 220 nm, which is sensitive to peptide bonds — as each molecule passes.
A pure compound shows a single sharp peak at its characteristic retention time, with the baseline flat on either side. Impurities show up as smaller peaks at different retention times. The chromatogram's central claim is that you can see, visually, how clean the sample is.
The purity calculation
HPLC purity is reported as an area-percent calculation. The integration software measures the area under each peak — the integrated signal over time, which is proportional to the number of molecules that contributed to that peak. The purity figure is the area of the main peak divided by the total area under all peaks, expressed as a percentage. A 98% purity figure means the main peak accounts for 98% of the total UV-absorbing material in the sample.
Two caveats on the percentage. First, the calculation assumes UV detection captures all the impurities, which is a fair assumption for peptide-related impurities but misses small molecules and salts that absorb weakly at 220 nm. Mass spectrometry covers that gap. Second, "98% pure" means 98% of the absorbing material is the target molecule; it does not mean the cartridge is 98% peptide by mass. The remaining 2% can include synthesis byproducts (truncated peptides, deamidated forms), residual solvents, and trace impurities from the synthesis route.
What mass spectrometry adds
The mass spectrometer ionizes the sample and measures the mass-to-charge ratio of every molecule in the spray. The result is a mass spectrum: peaks at specific mass values, where each peak corresponds to a molecule of that exact mass. For peptides, this is the identity check — the calculated mass of the target peptide (a function of its amino acid sequence) should match the observed mass on the spectrometer to within a few parts per million on a modern instrument.
The mass spec answers two questions HPLC cannot answer alone. Is this the right molecule? (The mass should match the theoretical molecular weight of the target peptide.) Are there mass-related impurities that would be invisible on UV detection? (Truncated peptides with one or two missing residues elute close to the target on HPLC but show up clearly on mass spec.)
An Aevum COA shows both: the HPLC chromatogram with the purity area-percent, and the mass spectrum with the observed mass for comparison to the theoretical mass. Together they verify that the molecule is the molecule we claim it is, and that the bulk of the sample is that molecule.
The lot identifier
The top of every COA carries a lot number — a unique identifier for the specific batch of compound the COA was issued against. Every cartridge crimp on our pre-filled cartridges is laser-etched with the same lot number. If you have cartridge LOT 04/26, you can pull the COA for LOT 04/26 and confirm that the chromatogram and spectrum on file describe the exact material in your cartridge. This is what "lot-tracked release testing" means: there is no aggregated "typical purity" claim, there is a specific COA for the specific batch.
What a COA does not show
A COA is a snapshot of identity and purity at the time of testing. It does not tell you whether the compound was handled correctly after the test — that is what the cold-chain logger is for. It does not tell you the compound is safe or effective for any particular use; for research-grade compounds the COA is silent on use cases, because the document is a chemistry certification, not a medical claim. And it does not certify sterility unless an explicit sterility test was performed; standard HPLC and mass spec do not assess microbial contamination.
The COA's value is exactly what it certifies: this molecule, in this lot, was this pure when an accredited third-party lab measured it. That is a narrower claim than "this product is safe," but it is also a more rigorous one — and for a research workflow, that is the right kind of rigor.