Does a traceable standard remove the need to assess real samples?
No. It supports a defined performance check. Sample-specific preparation, optical assumptions and method suitability still require evaluation.
Distinguish instrument verification from application-method evaluation. A suitable standard can check performance under specified conditions, while a real sample may introduce different dispersion or sampling questions. Retain the material certificate, handling conditions and acceptance basis with the verification record.
How should a laboratory use a particle reference material?
Microtrac identifies a nominal 0.450 µm polystyrene suspension for a wet recirculating laser-diffraction check. Read the lot certificate for the assigned property and uncertainty, then measure under the specified conditions. Use the laboratory’s defined acceptance rule and retain the observed result with the certificate.
Method details to record
| Consideration | What to record |
|---|---|
| Reference selection | Assigned property and suitability |
| Handling record | Preparation and certificate information |
| Decision rule | Acceptance criteria and follow-up |
What if the reference passes but production samples vary?
Test independently prepared portions of the production material. Variation between those portions can reveal sampling or dispersion effects that a stable reference misses. Investigate changes to the product method separately from instrument verification.