Overview
ISO 13318-1:2024 specifies the general principles, requirements, and guidance for determining particle size distribution by centrifugal liquid sedimentation (CLS) methods. A globally recognized standard developed by ISO, this document provides comprehensive guidance for laboratories, manufacturers, and researchers working in material characterization, quality control, and research and development across diverse industries.
CLS techniques separate particles from a low-concentration dispersion under centrifugal force, enabling precise measurement of particle sedimentation velocities and calculation of size distributions. ISO 13318-1:2024 defines essential terminology, covers measurement methodologies, and guides users on sample preparation, the measurement process, data analysis, method validation, and uncertainty determination.
Key Topics
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Principles of Centrifugal Liquid Sedimentation (CLS):
- Explained as the directed migration of particles in a liquid under centrifugal force.
- Relates sedimentation velocity and the sedimentation coefficient to particle size, shape, and density.
- Assumes isolated particle behavior at low concentration for accurate particle size analysis.
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Measurement Techniques:
- Homogeneous-start method (HSM): Involves mixing particles uniformly within the measurement cell.
- Line-start method (LSM): Particles are introduced as a thin layer, forming a distinct boundary for sedimentation.
- Guidance for both incremental (HSM/LSM) and integral measurement approaches.
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Sample Preparation and Analysis:
- Recommendations for dispersing particles in Newtonian liquids and preventing aggregation.
- Preparation steps for both the continuous phase and dispersed sample to ensure reproducibility.
- Handling of non-spherical and porous particles for accurate characterization.
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Data Acquisition and Evaluation:
- Best practices for conducting measurements and monitoring the sedimentation process.
- Methods to analyze data, derive particle size distributions, and represent results.
- Consideration of Brownian motion effects, determination of overall and fractional particle concentrations, and managing working ranges for size and concentration.
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Validation & Uncertainty:
- Procedures for method validation, system qualification, and performance verification.
- Approaches for calculating and presenting measurement uncertainty and expanded uncertainty.
- Use of reference materials, trueness, reproducibility, and accuracy assessment.
Applications
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Quality Control in Manufacturing:
Ensure product consistency in industries such as pharmaceuticals, pigments, food, and coatings by characterizing the particle size distribution of raw materials and finished products.
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R&D in Material Science:
Support research into nanoparticles, emulsions, suspensions, and novel materials by providing reliable particle size data.
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Environmental and Health Monitoring:
Analyze pollutant particulates or biomedical samples where fine particle size information impacts safety or efficacy.
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Analytical Research Laboratories:
Adopt standardized methods for routine characterization of dispersions, ensuring data comparability and reproducibility worldwide.
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Instrument Compliance and Validation:
Enable manufacturers and calibration laboratories to validate particle sizing instruments according to recognized international standards.
Related Standards
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ISO 9276-1:
Representation of results of particle size analysis – Part 1: Graphical representation.
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ISO 13317-series:
Particle size analysis by gravitational liquid sedimentation methods, providing complementary methodologies.
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ISO 26824:
Terminology and basic requirements for particle characterization.
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ISO 15901-1:
Determination of pore size distribution and porosity.
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ISO 18747-1 and ISO 18747-2:
Guidance for determination of solid particle density and related properties.
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ISO/IEC Guide 98-3:
Guidance on the expression of measurement uncertainty.
Practical Value
Implementing ISO 13318-1:2024 enhances the accuracy, reliability, and comparability of particle size measurements by enforcing robust standard practices for CLS. Utilizing this standard minimizes measurement variability, supports regulatory compliance, and improves quality assurance throughout the particle characterization workflow – from sample preparation to data interpretation and reporting.
By adhering to these guidelines, organizations gain confidence in their analytical results and maintain harmony with global best practices in particle size measurement and reporting.