Peptide Purity vs. Peptide Identity
Purity and identity are related but separate analytical attributes. A high purity percentage does not, by itself, prove that the principal component is the intended peptide.
What purity measurements describe
Reverse-phase HPLC commonly separates detectable sample components under specified chromatographic conditions. An area percentage reports the relative detector response assigned to resolved peaks. Interpretation depends on the method, wavelength, integration, reference materials, and the compounds that the detector can observe.
What identity testing addresses
Mass spectrometry can compare an observed mass-to-charge pattern with the expected molecular mass. Other identity techniques may be appropriate depending on the material. Identity evidence asks whether the measured compound is consistent with the intended molecule; purity asks how the measured sample is distributed among detectable components.
Why both questions matter
A sample may produce one dominant chromatographic peak while still requiring independent identity confirmation. Conversely, a mass consistent with the expected molecule does not quantify every impurity. Researchers should avoid treating either result as a complete characterization.
How to review a lot record
- Confirm the compound and lot identifiers match the supplied vial.
- Identify the analytical methods used.
- Review the reported result and any stated limitations.
- Distinguish purity, identity, and labeled quantity.
- Check the issuing laboratory and report date.
JD BioWorks plans to associate each product with its exact lot-specific COA. Until a lot record is published, the product page should be treated as a specification page rather than a substitute analytical report.
Next: HPLC vs. LC-MS and lot traceability.