A Certificate of Analysis is the single most useful document in this industry, and most people never open theirs. It looks technical. It isn't. Here's every line that matters.
Line 1: Lot / Batch Number — the important one
Start here, always. This is the batch fingerprint. It must match the number printed on your vial.
If it doesn't match, the certificate describes someone else's product. A supplier who sends every customer the same COA is not documenting your material — they're showing you a brochure.
Line 2: HPLC Purity
HPLC separates a sample into its components and measures each one. You'll see a percentage and usually a chromatogram — the graph with peaks.
Reading the graph is easier than it looks: one tall peak is good. Several significant peaks means several substances are present.
Line 3: Mass Spectrometry
Purity tells you how much. Mass spec tells you what. It measures molecular weight, and you'll see two numbers — theoretical and observed. They should closely agree. If they don't, the material is not what the label says.
This is the check that catches the worst-case scenario: a vial containing the wrong compound entirely.
Line 4: Appearance
Usually reads "white to off-white lyophilized powder." Lyophilized just means freeze-dried. Compare it to what's actually in your vial — discoloration or unexpected clumping is worth raising.
Line 5: Test Date and Testing Facility
When, and by whom. A COA with no date or no named laboratory is decoration rather than evidence. Independence matters here: a purity figure means more when the party measuring isn't the party selling.
Line 6: Water Content / Residual Solvent
Manufacturing leftovers. Small numbers are normal and expected. This is a completeness check, not a red flag.
Why purity is never 100%
Because 100% doesn't exist in peptide synthesis. Building a chain of amino acids produces some closely-related fragments alongside the target. A supplier claiming 100% is either rounding or not measuring.
The 30-second check
- Lot number matches your vial
- Purity meets the stated threshold
- Mass spec theoretical and observed agree
Those three lines tell you most of what a COA can tell you. Everything else is supporting detail.
Our full process, and how to request the certificate for your specific lot, is on the Quality & Testing page.
Dissolv products are supplied for laboratory research only and are not for human or veterinary consumption. Analytical documentation describes material as supplied and is not a claim of clinical safety or effectiveness.
