Overview
CEN ISO/TS 24672:2024 (identical to ISO/TS 24672:2023) is a technical specification for nanotechnologies that provides guidance on the measurement of nanoparticle number concentration in liquid dispersions and aerosols. It reviews both ensemble measurement techniques and particle counting methods, offering practical information on sample preparation, measurement use, advantages and limitations, and sources of uncertainty. The document is produced by ISO/TC 229 and adopted by CEN/TC 352.
Key topics
- Scope and terminology: Definitions, abbreviated terms and the recommended unit for number concentration (expressed as number of particles per unit volume).
- Technique categories:
- Ensemble approaches: Differential Centrifugal Sedimentation (DCS), Multi-Angle Dynamic Light Scattering (MDLS), Small-Angle X‑ray Scattering (SAXS), Ultraviolet‑visible spectroscopy (UV‑vis).
- Particle counting methods: Particle Tracking Analysis (PTA), Resistive Pulse Sensing (RPS), Single Particle ICP‑MS (spICP‑MS), Condensation Particle Counter (CPC) and Differential Mobility Analysing System (DMAS).
- Selection considerations: Guidance when choosing a method based on particle type, number concentration range, required accuracy/precision and other practical factors.
- Technical aspects: Sample specifications, instrumentation factors, data interpretation and common sources of measurement uncertainty for each technique.
- Practical support: Annexes summarizing interlaboratory studies (VAMAS) and general sample preparation guidance for suspensions with nanoparticles.
Practical applications and users
CEN ISO/TS 24672:2024 is relevant for organizations and professionals needing reliable nanoparticle number concentration data, including:
- Research laboratories and academic investigators studying nanomaterials.
- Metrology and testing laboratories performing characterization and quality control.
- Nanomaterials manufacturers validating product specifications.
- Environmental and occupational monitoring programs assessing airborne nanoparticle exposure.
- Regulatory bodies and standards developers seeking harmonized measurement guidance.
- Pharmaceutical and consumer product developers working with nanoparticle formulations.
Benefits and limitations
- Provides a comparative overview enabling informed method selection for different sample matrices and concentration ranges.
- Clarifies sample preparation, known uncertainties and practical challenges for each technique.
- Does not replace method-specific standards or protocols but complements them by summarizing strengths and limitations.
Related documents
- Published as ISO/TS 24672:2023 and endorsed as CEN ISO/TS 24672:2024. Users should consult technique-specific standards and normative references cited in the specification for detailed measurement procedures.