A Certificate of Analysis is the single most important document in research peptide sourcing. It is the independent evidence of what a vial actually contains — and any supplier unwilling to produce one per batch should be disqualified immediately. This guide walks through each section of a COA and what a careful laboratory should look for.
Identity Verification
The first thing a COA establishes is that the compound is what the label claims. This is typically done by mass spectrometry: the measured molecular weight is compared against the theoretical mass of the target sequence. A match within tight tolerance confirms identity; a mismatch means the vial contains something else entirely — the most serious failure a COA can reveal.
Understanding Peptide Purity Through HPLC Analysis
Purity is measured by high-performance liquid chromatography. The compound is passed through a column that separates molecules, producing a chromatogram — the graph of peaks most people picture when they think of a COA. The main peak is the target peptide; smaller peaks are impurities such as truncated sequences or synthesis byproducts. The purity percentage is the main peak area relative to the total. Research-grade material should show 99% or higher.
Batch and Lot Information
A legitimate COA is tied to a specific production lot, not the product in general. Check that the lot number on the certificate matches the vial label, and that the analysis date is plausibly recent. A supplier reusing one generic COA across every batch is not actually testing every batch.
Red Flags When Evaluating Suppliers
Watch for: certificates with no lot number, purity claims with no chromatogram, in-house-only testing with no independent laboratory named, stock photos of certificates rather than batch documents, and suppliers who cannot produce a COA on request. Each is a sign the testing story is marketing rather than quality control.
How Pristine Aminos Handles Testing
Every batch we sell is independently third-party tested for identity and purity at 99% or higher, and ships with its Certificate of Analysis. Documentation lives where a researcher can find it — see our Testing page for current documentation, and every product page carries batch verification details.
All products referenced are intended strictly for in-vitro research and laboratory use only. They are not for human or veterinary use, consumption, or therapeutic application.