Batch And Identity Information
Every COA is tied to a specific batch or lot number. The document should state the compound name, the batch identifier, the molecular formula, and the theoretical molecular weight. The batch number is what links the certificate to the physical vial in your hands; a COA that cannot be matched to a batch is of limited value.
Purity By HPLC
High-Performance Liquid Chromatography (HPLC) is the standard method for reporting peptide purity. The COA typically lists a purity percentage, often expressed as area-under-the-curve at a specified wavelength. A chromatogram may be included, showing a dominant peak for the target compound and any minor peaks representing impurities.
Higher purity is generally preferable for research reproducibility, though the acceptable threshold depends on the intended experiment. What matters is that the number is reported, the method is stated, and a chromatogram supports the claim.
Identity By Mass Spectrometry
Mass spectrometry (MS) confirms the identity of the peptide by measuring its molecular mass. The COA compares the observed mass against the theoretical mass calculated from the sequence. A close match confirms that the synthesized compound is the intended molecule, not a different or incorrectly assembled sequence.
What To Check Before Trusting A COA
A credible COA is specific, method-referenced, and batch-linked. Treat a certificate with caution if it lacks any of the following.
- A batch or lot number that matches the vial.
- A stated purity figure with the analytical method named (for example, HPLC at a given wavelength).
- A mass spectrometry result comparing observed versus theoretical mass.
- Supporting chromatograms or spectra rather than a bare summary number.
- The testing party identified, ideally an independent or third-party laboratory.
Research Use Only: This guide is informational and describes research-context handling of compounds intended strictly for in vitro laboratory research. Products are not for human or animal consumption, ingestion, or injection, and are not FDA-approved. Nothing here is medical, clinical, or dosing advice.
Frequently Asked Questions
What is a Certificate of Analysis (COA)?
A COA is the primary quality document for a research peptide. It reports the analytical testing performed on a specific batch, letting a researcher confirm the identity and purity of the material before use.
How is peptide purity shown on a COA?
Purity is typically reported by HPLC as a percentage, often with a supporting chromatogram. Mass spectrometry is used separately to confirm the compound identity against its theoretical molecular weight.
How do I know a COA is trustworthy?
A credible COA is batch-linked, names the analytical method, includes a mass-spectrometry identity result, and is supported by chromatograms or spectra. Always match the COA batch number to the physical vial.