Overview
ISO 19430:2024 - Determination of particle size distribution and number concentration by particle tracking analysis (PTA) - specifies a standardized PTA method under static (no‑flow) conditions to measure number‑based particle size distribution and particle number concentration in liquid dispersions (solid particles, liquid droplets or bubbles). The second edition expands the first (2016) by adding particle counting, gravitational fall tracking, multispectral detection, and guidance on serial dilution and method comparisons. ISO 19430:2024 covers theory, limitations and advantages of PTA, common instrument configurations, measurement procedures, system qualification and reporting.
Key topics and technical requirements
- Measurement scope
- Determines number‑based size distributions and total particle number concentrations in liquid suspensions.
- Two tracking regimes: Brownian motion tracking for smaller particles and gravitational fall (sedimentation) tracking for larger particles.
- Principles and limits
- Explains relationships between Brownian diffusion, Stokes law and hydrodynamic diameter.
- Defines limits of detection (lower/upper size limits, number concentration limits), sensing and sampling volume considerations.
- Apparatus & data capture
- Addresses required components: sample cell, illumination, optical image capture (video), and image‑analysis/tracking software.
- Notes commonly used instrument configurations and simultaneous multispectral detection options.
- Measurement procedure
- Standardized steps for sample preparation, instrument set‑up, illumination, video capture, track analysis, sizing and counting, background subtraction and results evaluation.
- Quality & qualification
- System installation, maintenance and operation requirements.
- Instrument qualification protocols for sizing and for number concentration measurements, plus ongoing quality control and data recording.
- Supporting material
- Informative annexes on theory, comparative concentration studies (e.g., gold nanoparticles), sedimentation use, and serial dilution experiments.
Applications and users
ISO 19430:2024 is practical for laboratories and organizations needing robust particle sizing and counting in liquid dispersions:
- Who uses it: analytical labs, nanomaterials researchers, pharmaceutical formulation teams (liposomes, exosomes, viruses), toxicologists, cosmetics and food quality control, ink/paint manufacturers, fuel additive developers, and regulators.
- Typical applications: nanoparticle characterization, quality control of suspensions, formulation development, nanotoxicology studies, measurement of protein aggregates, pigment/ink particle sizing, and validation of particle counting for regulatory compliance.
Related standards
- ASTM E2834 (NTA guidance) - referenced as prior guidance for nanoparticle tracking analysis.
- Developed by ISO/TC 24/SC 4 (Particle characterization).
ISO 19430:2024 provides a comprehensive, standardized framework for accurate PTA‑based particle sizing and counting, enabling comparable results across laboratories and applications.
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