What a peptide certificate of analysis shows

A certificate of analysis, or COA, is the release document for a batch. It records what the batch is and what it was tested to before it shipped. Every box carries one, and you can pull it yourself from the batch number.

What it reports

Identity. That the material is the peptide on the label, confirmed by retention time on RP-HPLC against a reference standard and by mass on ESI-MS.
Purity. The main-peak area by RP-HPLC, held to not less than 98.0 percent, with any single related substance held under 1.0 percent.
Water content. By Karl Fischer, since a lyophilised powder holds a little residual water.
Content. The labelled peptide mass per vial, to within plus or minus 5 percent by weight.
Dates. The release date and the retest date, so you know how long the figure stands.

How to read a result

Purity is an area figure at 220 nm: a 99.1 percent result means 99.1 percent of the peak area is the main peak, and the rest is related substances, each below the 1.0 percent limit. Identity is a yes on two independent methods, retention and mass, not one. The controlling document for any given box is its own certificate, not a reference table.

Verify a batch

The batch number is printed on the vial label, the carton and the packing list. Enter it in the COA lookup to pull the certificate on file, no sign-in needed. If a number does not resolve, the desk can confirm it. How a batch is built and released is on the quality page.

Common questions

What purity are the peptides held to?

Not less than 98.0 percent by RP-HPLC area at 220 nm, with any single related substance under 1.0 percent. The batch certificate carries the actual figure.

How do I get the COA for my batch?

Enter the batch number from the label or packing list in the COA lookup. No sign-in is needed.

Is the certificate batch-specific?

Yes. Each certificate is the release document for one batch, and its batch number matches the number on the vial.