How to Read a Certificate of Analysis

Every batch on this site links to a Certificate of Analysis (COA): the report from the laboratory that tested it. A COA is only useful if you know what to look for, so this guide walks through a certificate section by section.

1. The header: what was tested, and when

The top of a COA identifies the sample. Check for the compound name and amount, a batch or lot number, the date the sample was tested, and the name of the laboratory that ran the analysis. Without a batch number and a test date, a certificate cannot be tied to anything you received.

2. Identity: is it the right molecule?

Identity is usually confirmed by mass spectrometry. Every peptide has a theoretical molecular mass based on its amino acid sequence. The laboratory measures the mass of the sample and compares the two. A close match confirms the compound is what the label says it is. Purity on its own cannot tell you this, because a sample can be very pure and still be the wrong peptide.

3. Purity: how much of the sample is that molecule?

Purity is normally measured by high-performance liquid chromatography (HPLC). The sample is separated into its components, and each shows up as a peak. Purity is the main peak expressed as a percentage of everything detected. A result of 99% means that around 1% of what the instrument detected was something else, such as truncated sequences or by-products of synthesis.

4. Other tests

Depending on the certificate, you may also see an assay or potency result (how much compound is actually present against the amount stated), heavy metals, residual solvents left over from manufacturing, and water content. Each one answers a different question about the quality of the batch.

5. Match the certificate to your order

The most important check is the simplest: the batch details on the certificate should match the label on the product you received. If you are unsure which certificate applies to your order, contact us with your order number and we will confirm it.

Red flags on any supplier's COA

• No batch or lot number, or no test date.
• No laboratory named on the report.
• A purity figure with no method stated.
• The same certificate used for several different products or batches.
• A screenshot of a chromatogram with no results table.

You can browse every published Meytrix certificate on the COA page.

All Meytrix products are supplied for laboratory research use only and are not for human consumption.