How Our Batches Are Tested: Reading and Verifying a COA

We're a new UK supplier, and we know that "new" means you should verify rather than trust. This page explains where our test reports come from, what they show, and how to check the one for your vial.

Where our test reports come from

Batches are tested by the manufacturer at independent third-party laboratories, including Janoshik Analytical, Accumark Labs, Freedom Diagnostics, Axiom Analytics Laboratories and others. We don't run our own in-house testing. Instead, we publish the reports we receive, organised by product and lot, in our verification library at verify.peptidestock.co.uk.

Matching your vial to its report

Every vial carries a lot number. Lot numbers follow the format CP01 + date of manufacture (YYMMDD) + product code + strength + suffix letter. To find the report for your vial, go to verify.peptidestock.co.uk/lot/ followed by your lot number.

Not every lot has a published report yet. If yours isn't listed, email info@peptidestock.co.uk with the lot number and we'll tell you what documentation is available.

What HPLC testing measures

High-Performance Liquid Chromatography (HPLC) separates the components of a sample and measures how much of it is the target peptide. A result of 99% means that 99% of the detected material is the intended compound. The purity figure for each lot is shown in the library.

Purity isn't identity

Purity tells you how clean a sample is, not what it is. Mass spectrometry (MS) confirms the molecular weight matches the expected peptide. Where a report includes MS or identity data, check that the measured mass matches the expected value for that compound.

Each result applies only to the lot tested

A report tells you about the specific lot that was sampled, not about other lots of the same product. Always match the lot number on your vial to the lot number on the report.

How to read a report

• Lot number – must match your vial.
• Laboratory – which lab carried out the test.
• Purity (%) – the HPLC result.
• Identity – MS confirmation of molecular weight, where included.
• Quantity – the measured content per vial against the labelled amount, where included.
• Verification code – some labs let you confirm a report on their own website. Where a report has a code, use it.

Questions about a lot?

Email info@peptidestock.co.uk with your lot number.

All products are sold strictly for laboratory research use only. They are not medicines and are not for human or veterinary use.