Glossary
Impurity profile
The described set of identified and unidentified impurities present in a material: specified impurities with their own limits, any unspecified impurities against a general limit, and a total. It characterises the material's purity beyond the assay figure.
Why it matters on a certificate
Impurities are where quality problems usually live. A certificate that reports assay but no impurity results, against a standard that specifies them, is silent exactly where scrutiny belongs. Reviewers also check arithmetic: individual impurities that sum to more than the reported total contradict the document.
A worked example
A certificate reports three named impurities at 0.1% each and a total impurities figure of 0.2%. The rows and the total cannot all be right, and the inconsistency is a finding independent of any limit.
Examples are synthetic and illustrative; any limits shown are not the requirements for any particular material.
The COA Validator checks the element this term describes on every certificate it reads, and reports what is present, what is missing and what does not add up.