NIST traceability is typically established by an unbroken chain of measurements, referencing particles to SRMs from NIST. As such, this is basically an internal method, relying on one’s own expertise and instrumentation, whereas the NanoStandard™ 17025 and MicroStandard™ 17025 size standards consists of material from the original batches certified by the Danish National Metrology Institute (DFM).
The DFM used Atomic Force Microscopy (AFM) measurements performed under DANAK accreditation no. 255, following DS/EN ISO/IEC 17025. DANAK (Danish Accreditation and Metrology Fund) is one of the signatories to the EA multilateral agreement and the ILAC multilateral agreement for the mutual recognition of calibration certificates.
ISO/IEC 17025 is a quality standard, founded by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). It is the definition of requirements for laboratories to ensure quality, reliability and repeatability of performed tests and calibrations.
The calibration method and certificate thus created ensures that Applied Microspheres’ NanoStandard™ 17025 and MicroStandard™ 17025 particle size standards are traceable to the International System of Units (SI), including NIST, and meet the criteria obligatory for instrument calibration under ISO/IEC 17025. They therefore meet the highest international metrological standard available.