Purity Testing Versus Identity Confirmation
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Why a high purity percentage does not establish that a compound is what the label says it is.
Different questions
Purity asks how much of the detected material corresponds to the main component. Identity asks whether that component is the intended molecule. A sample can be highly pure and still not be the labelled compound.
How purity is measured
HPLC separates components and integrates peak areas. The reported figure is a relative measure under the conditions of that method.
How identity is supported
Mass spectrometry compares the observed mass with the theoretical mass derived from the sequence. Sequencing methods provide further support where used.
Practical implication
Where a supplier publishes only purity data, identity has not been demonstrated for that lot, and product pages should not imply otherwise.
This page is laboratory reference material. It does not describe suitability for human or veterinary use.
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