Peptide content testing

What a content test answers

You cannot see mass. A vial can hold a fraction of the stated peptide, padded out with excipient, and look exactly like a correctly filled one. Underdosed and overdosed vials are indistinguishable until something measures them.

Content is the quantitative test: the amount of peptide in the vial as supplied, reported against the amount you declared when you ordered.

Why it is different from purity

HPLC purity compares the peptide with the other UV-absorbing material in the sample. It cannot see water, salts or counter-ions, so a vial can be 99% pure and still contain noticeably less peptide than the label says. Content answers the question purity cannot: how much is there.

What the certificate reports

• The measured amount of peptide in the vial as supplied
• The amount you declared, for comparison
• Method and the named analyst
• A COA number anyone can check at Verify a COA

How to order

1. Create a free account. Individual or business; an individual account needs only an email address.
2. Build the order and submit it. One row per sample. Choose a package that includes content.
3. Get your chain-of-custody form and payment link. Both are emailed the moment you submit and saved on the order in your account.
4. Post the vials. Write each Sample ID on its vial and on the package, and add your tracking number to the order.

Sample requirements

For lyophilized powder, 2 mg or more per vial is ideal; we can usually work with less and will tell you before we start if the amount is marginal. For reconstituted solution, send at least 0.5 mL. This test is subdivided from the same vial as the sample’s other tests. Pro 7X takes two vials of the same sample, because it includes sterility.