Overview
EN ISO 21363:2022 (ISO 21363:2020) defines standardized procedures for using transmission electron microscopy (TEM) to measure particle size and shape distributions. The standard specifies how to capture, measure and analyse TEM images to produce reproducible, traceable nanoscale particle statistics. It applies broadly to nano-objects and also to particles larger than 100 nm; the practical working range depends on the required measurement uncertainty and the performance of the TEM.
Key topics and requirements
- Scope & applicability: Guidance for TEM-based size/shape measurement across nanotechnologies, including limits tied to instrument performance and uncertainty needs.
- Sample preparation: Selecting representative samples, minimizing agglomeration, and choosing suitable mounting supports to avoid bias in particle distributions.
- Instrument factors & calibration: TEM setup, use of calibration standards and calibration procedures to ensure accurate dimensional scaling.
- Image capture: Recommendations on magnification selection, minimum particle area, frame selection, and number of particles to image for statistically meaningful distributions.
- Particle analysis: Individual and automated particle analysis workflows, including segmentation, handling touching particles, and artifact exclusion.
- Data analysis & statistics: Data triage, distribution fitting, repeatability/intermediate precision/reproducibility assessment, and approaches to estimate measurement uncertainty for fitted parameters and size descriptors.
- Reporting: Required information to document methods, results and uncertainties so measurements are comparable across labs.
- Informative case studies: Annexes illustrate common sample types (aggregates, mixtures, nanofibres, crystal habits) and practical examples for analysis.
Practical applications
- Characterizing nanoparticle size distributions and particle morphology for R&D, quality control, regulatory compliance and material certification.
- Comparing production batches in manufacturing (paints, catalysts, pharmaceuticals, electronics).
- Supporting toxicology and environmental studies where particle size/shape influence behavior.
- Validating imaging and automated image-analysis workflows in analytical laboratories.
Who should use this standard
- TEM laboratory managers and microscopists
- Metrology and quality assurance teams in industry
- Nanomaterials researchers and product developers
- Accreditation bodies and regulatory agencies requiring traceable particle-size data
Related standards and context
EN ISO 21363:2022 is part of ISO/CEN work on nanotechnologies and complements other metrology and microscopy standards addressing instrument calibration, uncertainty evaluation, and nanoparticle terminology. For full implementation, users should consult national standards bodies or the ISO catalogue for associated guidance documents.
Keywords: EN ISO 21363:2022, ISO 21363, transmission electron microscopy, TEM, nanoparticle size distribution, particle shape distributions, nanotechnologies, measurement uncertainty, sample preparation, image analysis.