Certificate of Analysis (COA)
Definition
The analytical report for one batch, stating identity, purity and whatever else was tested. Its worth depends entirely on who ran the tests and on whether the batch number matches the material in hand, which is what makes a batch number worth checking rather than glancing at.
In more detail
A certificate of analysis reports what was measured on a specific lot, against the specification that lot was released to. Its value rests on being specific: a document that names no lot, no method and no laboratory describes nothing that can be checked.
The fields worth reading first are the ones that tie the document to the material in hand. A lot number that matches the vial, a date, the named laboratory, and the methods used for each result. After that, whether acceptance criteria appear beside the results, because results alone are observations rather than a release decision.
It is also the most forgeable document in this trade, which is why a laboratory's own verification page matters more than the file. A report that can be looked up at source is one a supplier cannot have edited.
What this means for research sourcing
Purity and identity verification are central to research reproducibility. Every Volta compound ships with >99% HPLC-verified purity and a certificate of analysis.
Related Terms in Quality
HPLC (High-Performance Liquid Chromatography)
The separation technique behind the purity figure on a certificate. A sample is pushed through a packed column under pressure and the components come off at different times, so a 99% result means 99% of what the detector saw was the target peak.
Chromatography
Any technique that separates a mixture by how its components distribute between a moving phase and a stationary one. Reversed-phase liquid chromatography is the version peptide work almost always means.
Mass Spectrometry (MS)
Measurement of the mass-to-charge ratio of ionised molecules, used to confirm that the observed mass matches the mass the sequence predicts. It supports identity; on its own it does not prove the full sequence, since rearrangements can share a mass.
Amino Acid Analysis (AAA)
Hydrolysing a peptide back to its constituent amino acids and quantifying each one, which gives composition and total peptide content. It answers a question HPLC does not: how much peptide is actually in the vial.
Net Peptide Content
The share of the powder that is peptide, once counter-ions and residual water are accounted for. Gross vial weight is always higher, so purity and content are two separate numbers and neither substitutes for the other.
Karl Fischer Water Determination
The standard laboratory assay for water content in a dry solid, using an iodine reaction specific to water. On a lyophilised peptide it reports residual moisture, which is a stability predictor, and the result is reported as a mass fraction of water in the solid.
Purity
The proportion of a sample that is the intended peptide rather than related impurities, measured chromatographically and quoted as a percentage. It says nothing about identity, sterility or endotoxin content, each of which is a separate test. Volta releases every batch against a >99% HPLC specification.
Endotoxin
Lipopolysaccharide from the outer membrane of Gram-negative bacteria. It survives ordinary sterilisation and is not removed by filtration alone, and it provokes a febrile inflammatory response, which is why it is assayed separately from sterility.
