Overview
ISO 19430:2016 - "Particle size analysis - Particle tracking analysis (PTA) method" defines how to evaluate a number-based particle size distribution of particles suspended in liquids using Particle Tracking Analysis (PTA, also known as Nanoparticle Tracking Analysis, NTA). The standard describes the underlying principles (Brownian motion and the Stokes–Einstein relationship), required apparatus and settings, step-by-step measurement procedures, system qualification, quality control, data recording and reporting. The key measurand is the hydrodynamic diameter of individual particles derived from diffusion velocity measurements.
Key topics and technical requirements
- Principles: Measurement is based on imaging laser-illuminated particles undergoing Brownian motion; the hydrodynamic diameter is calculated using the Stokes–Einstein equation.
- Measurand: Number‑based particle size distribution reported as hydrodynamic diameter.
- Detection and accuracy: Discussion of detection limits, measurement accuracy and limitations inherent to PTA.
- Apparatus: Requirements and recommendations for illumination, imaging, sample delivery and detection hardware.
- Procedure: Detailed workflow covering sample preparation, instrument set-up and initialization, measurement (sample delivery, illumination, particle imaging and tracking), track analysis and distribution evaluation.
- Quality systems: System installation, maintenance, operation, qualification and routine quality control tests to ensure reliable PTA performance.
- Data handling & reporting: Guidance on data analysis, result evaluation, recording and preparation of test reports; annexes provide theory, best-practice apparatus settings and reporting templates.
Practical applications and who uses it
ISO 19430:2016 is intended for laboratories, instrument manufacturers, quality control teams and researchers who require robust particle sizing by PTA. Typical application areas include:
- Nanomaterials characterization and regulatory compliance
- Biopharma (liposomes, exosomes, viruses, protein aggregation)
- Nanotoxicology and academic research
- Formulation and QC for inks, pigments, cosmetics and fuel additives
- Food science and characterization of suspensions and fine bubbles
PTA is especially useful when a number-based size distribution and individual-particle analysis across a broad submicron range are required (e.g., when comparing results with dynamic light scattering or electron microscopy).
Related standards
- ISO 13322-1 (Image analysis methods) - referenced for static image analysis context
- ISO 26824 (Particle characterization vocabulary)
- ASTM E2834 (Guide for NTA) - earlier industry guidance referenced in ISO 19430 development
- Relevant ISO/TS documents on nanoscale terminology cited in definitions
ISO 19430:2016 provides a practical, standardized framework for consistent PTA measurements, improving comparability and traceability of particle size data across research, regulatory and industrial settings.