Purity
Purity is the share of a product that is the named compound itself, usually written as a percent. A 99% pure material is 99% that one compound and 1% everything else.
Where the word comes from
Purity comes from the Latin purus, meaning “clean, unmixed.” Latin speakers built the noun puritas from it, and the word came into English through French. Chemists have used it for centuries to mean a material free of other substances. The modern habit of stating purity as an exact percent, measured by an instrument, came with the analytical methods of the 1900s.
What it means here
Research depends on knowing what is actually in the vial. If a material is not pure, a lab cannot tell whether a result came from the compound or from something mixed in with it. Labs measure purity with instruments such as HPLC and mass spectrometry, and the measured number for each batch is recorded on its Certificate of Analysis. A purity figure is a lab measurement, not a quality slogan — it should always trace back to a real test on a real lot.
Words you’ll see together
- ≥99% — a common way a purity floor is written; “at least 99 percent”
- by HPLC — the tag that names the instrument behind the percent
- impurity — everything in the material that is not the named compound
- specification — the minimum a batch must meet to pass
- lot number — the batch code a purity result is tied to
Related terms
- HPLC — the main instrument labs use to measure a purity percent
- Mass spectrometry — confirms the compound’s identity alongside the purity test
- Certificate of Analysis — the batch report where the purity result is written down
- Endotoxin — a separate test for bacterial residue; high purity does not cover it
Where it appears in our catalog
- Purity and testing FAQ — how our batches are tested and what the numbers mean
- Reading a Certificate of Analysis — a walkthrough of where purity sits on the report
- BPC-157 — a product page with its purity spec listed
References
- Chawathe A, Sharma N (2026). LC-HRMS stability profile of afamelanotide: 14 distinct degradation products under acid/base/oxidative/UV/thermal stress. J Pharm Biomed Anal. PMID 41547183
- Artemis Labs, Purity and testing FAQ
