Reading the result
The chromatogram shows detector signals as peaks over time. A peak-area purity result compares the assigned target peak with other detected peaks under that method.
Keep the method in view
Detector response, separation and which components are detected affect the result. A purity percentage alone does not describe substances the method misses or establish measured milligram content.
What to ask for
Review the lot, method, result and supporting trace. Ask the laboratory to explain unclear peaks or calculations rather than judging a report from its headline number alone.