Laboratory guide
How to read a peptide Certificate of Analysis
A useful COA connects a specific sample to a specific method and result. The headline percentage is only one part of that record.
Start with the sample record
Confirm the report number, compound, client-facing identifier, lot or batch, sample form, and dates. A COA cannot be transferred to another vial or batch simply because the label looks the same. The report should say that its conclusions apply only to the sample received.
Identify what was actually measured
“Purity,” “identity,” and “content” are not interchangeable. HPLC area purity describes the share of detected chromatographic signal assigned to the main peak under stated conditions. LC-MS supports identity using mass data. Quantitative content estimates how much target analyte is present. Look for a named method beside every result.
Read the chromatogram in context
A chromatogram should label axes, the principal peak, and relevant integration. A visually clean trace is not proof that every possible impurity is absent: detection wavelength, resolution, sample preparation, and co-elution all affect what can be seen.
Check units, reporting limits, and specifications
Content may be reported in milligrams, concentration, or another agreed basis. Endotoxin and elemental results use different units. “Pass” or “fail” is only meaningful when a specification and its source are stated; otherwise, the laboratory should report the measured value without implying a universal acceptance limit.
Verify the source
Use the QR code or type the report number into the laboratory’s public registry. Check that the live page matches the analyte, dates, and report ID on the document. A verification page helps detect altered or reassigned reports, but it does not expand the scope of the testing.
Keep the limitations
A peptide COA does not automatically establish clinical safety, efficacy, sterility, legal status, or batch-wide uniformity. Those conclusions require different evidence. Canada Peptide Testing states these limits directly on each report.