How to Read a Certificate of Analysis
Your COA contains critical data about the compound you're working with. We walk through each section and what to look for.
A Certificate of Analysis (COA) is the single most important document you receive with a research peptide. It contains the analytical data that tells you exactly what's in the vial — the compound's identity, purity, and physical characteristics. Every decision about whether to trust a product starts here.
But COAs aren't always straightforward. This guide walks through each section of a standard peptide COA so you know what you're looking at and what actually matters.
Header Information
The top of the COA should identify the product, the batch, and the testing party. Key fields include the compound name (both common name and sequence if applicable), the batch or lot number, the date of manufacture, the date of analysis, and the name of the testing laboratory.
The batch number is critical. It should be unique and traceable. If you ever have a question about a product, the batch number is what the supplier uses to pull complete production records. If a COA lacks a batch number, that's a significant red flag — it suggests the document may be templated rather than batch-specific.
Appearance and Physical Properties
This section describes the product's visible characteristics: typically a white to off-white lyophilized powder for most peptides. It may also include solubility data — for example, "soluble in sterile water at 1 mg/mL."
While this seems basic, it serves as a quick sanity check. If your vial contains a yellow or brown powder and the COA says white, something is off. Discoloration in lyophilized peptides can indicate oxidation, contamination, or improper storage.
HPLC Purity
This is the headline number most researchers look for. It's expressed as a percentage — for example, 99.2% — and represents the proportion of the sample that consists of the target peptide versus total detectable material.
The COA should specify the HPLC method used (typically reverse-phase C18), the mobile phase composition, and the detection wavelength (usually 220 nm for peptide bonds). Some COAs include the actual chromatogram; others provide only the numerical result.
For research-grade peptides, >99% purity is the standard to expect. Anything below 95% is generally considered insufficient for most applications. If a COA shows high purity but doesn't specify the method, the number is unverifiable.
Mass Spectrometry Results
The MS section confirms the molecular identity of the compound. You'll see two key numbers: the expected (theoretical) molecular weight calculated from the amino acid sequence, and the observed molecular weight measured by the instrument.
These should match within tight tolerances — typically within 0.1% or ±1 Da for peptides under 5,000 Da. A significant discrepancy indicates the sample may contain the wrong compound, a truncated sequence, or a chemically modified variant.
Some COAs report the mass spectrum itself (a graph showing peaks at specific m/z values). The dominant peak should correspond to the expected molecular weight.
What a Good COA Looks Like
A trustworthy COA has these characteristics: batch-specific data (not generic), both HPLC and MS results, clearly stated methods, a named testing laboratory, dates that make sense relative to your order, and results that are consistent with published data for the compound.
At Point Break Compounds, every COA includes all of these elements. We don't ship a product without one, and we don't release a batch that doesn't meet our >99% purity threshold. If you ever want to verify a COA, our support team can provide additional documentation tied to the specific batch number on your order.