COA Verification Guide

Identity testing: LC-MS

LC-MS provides mass evidence supporting compound identity. Matching mass alone does not establish sequence, purity or quantity.

Purity testing: HPLC

HPLC peak-area purity measures the relative detected signal under a stated method, not peptide milligrams per vial.

Net content verification

A documented quantitative assay measures compound amount. Powder weight and peak-area purity alone do not verify net peptide content.

Sterility testing

Sterility testing checks for viable microorganisms under specified test conditions. It does not measure endotoxin.

Endotoxin testing

LAL or validated recombinant assays measure bacterial endotoxins. Check the method, units and detection limits.

Heavy metal testing

ICP-MS or another validated elemental assay measures the specified elements, not every possible contaminant.

How to read, verify, and evaluate any peptide Certificate of Analysis, including the RUO Codes minimum standard.

What is a Certificate of Analysis?

A Certificate of Analysis (COA) is a lab report, ideally from an independent third-party lab, that documents the identity, purity, and quantity of a compound. For research peptides, a COA is the most important document a vendor can provide because it supplies independent evidence that the product matches its label.

The RUO Codes minimum COA standard

To be listed on RUO Codes, vendors must provide COAs that demonstrate: (1) net content, the total amount of peptide in the vial; (2) net purity, the percentage of peptide relative to total material; and (3) compound identity, confirmed via mass spectrometry or another validated analytical method.

Extra credit tests

The highest-tier vendors go beyond the minimum and include endotoxin testing (LAL or rFC), sterility testing, heavy metal screening (ICP-MS), and conformity testing. These are visible on each vendor's detail page on RUO Codes.

How to spot red flags in a COA

Watch for: in-house testing only (no independent lab); purity listed without the method used; no identity confirmation; COA dates that never change (suggesting a single lot being reused); or a COA with a different vendor's name than the one selling the product.

The 7-step COA verification checklist provides a structured reference for reviewing a Certificate of Analysis.

Use the AI-Assisted COA Check

Upload any peptide vendor COA to the AI-Assisted COA Check for a structured review against our verification standard.