ISO 13099-2-2025 PDF

Full title and description

St ISO 13099-2-2025 — Colloidal systems — Methods for zeta-potential determination — Part 2: Optical methods. This international standard specifies optical techniques for measuring the electrophoretic mobility of particles in liquid dispersions, principally video microscopy and electrophoretic light-scattering, and provides requirements for measurement procedure, data handling and reporting.

Abstract

This document specifies two methods of measurement of the electrophoretic mobility of particles suspended in a liquid: video microscopy and electrophoretic light‑scattering. Estimation of surface charge and determination of zeta‑potential can be achieved from the measured electrophoretic mobility using appropriate theoretical models described in ISO 13099‑1.

General information

• Status: Published (current international standard).
• Publication date: August 2025 (Edition 2, 2025).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 19.120 — Particle size analysis; sieving / particle characterization.
• Edition / version: Edition 2 (2025).
• Number of pages: 21 pages.

Scope

ISO 13099-2:2025 covers optical techniques for determining electrophoretic mobility of dispersed particles, specifically: (1) video microscopy approaches that track particle motion under an applied electric field, and (2) electrophoretic light‑scattering methods (including laser Doppler/electrophoretic light scattering). The standard sets out sample and instrument considerations, measurement conditions, data processing and the linkage to zeta‑potential estimation using models given in ISO 13099‑1. It replaces the earlier 2012 edition.

Key topics and requirements

• Defined measurement procedures for video microscopy and electrophoretic light‑scattering, including recommended experimental geometries and electrical field application.
• Sample preparation and handling guidance to minimise artefacts (contamination, aggregation, multiple scattering).
• Instrument calibration and verification practices, including reference materials and checks for field homogeneity and optical alignment.
• Data processing and analysis requirements: extracting electrophoretic mobility, statistical treatment, and uncertainty estimation.
• Requirements for reporting results (method identification, measurement conditions, derived zeta‑potential and the theoretical model used referencing ISO 13099‑1).
• Guidance on linking measured mobility to surface charge / zeta‑potential using the theoretical frameworks in ISO 13099‑1.

Typical use and users

Laboratories and quality departments performing colloid and nanoparticle characterisation; researchers in colloid science, environmental analytics and nanotechnology; instrument manufacturers and service providers that supply or validate electrophoretic light‑scattering and particle‑tracking equipment; regulatory and pharma analytical groups needing standardised zeta‑potential data for product characterisation and stability assessment.

Related standards

ISO 13099-1 (theoretical models and electroacoustic/electrokinetic methods) — referenced for model selection and interpretation. ISO 22412 (dynamic light scattering) is commonly used alongside ISO 13099‑2 for complementary optical particle characterisation. Other particle‑characterization standards from ISO/TC 24/SC 4 (e.g., laser diffraction, photon correlation methods) are relevant depending on the application.

Keywords

zeta potential, electrophoretic mobility, electrophoretic light scattering, video microscopy, colloidal systems, particle characterisation, ISO 13099, optical methods, particle tracking, uncertainty, sample preparation.

FAQ

Q: What is this standard?

A: ISO 13099-2:2025 is Part 2 of the ISO 13099 series and specifies optical methods (video microscopy and electrophoretic light‑scattering) for measuring electrophoretic mobility and supporting zeta‑potential determination.

Q: What does it cover?

A: It covers measurement procedures, instrument and sample considerations, data processing and reporting requirements for optical electrophoretic mobility methods, and refers users to ISO 13099‑1 for the theoretical models needed to convert mobility to zeta‑potential.

Q: Who typically uses it?

A: Analytical and research labs, instrument manufacturers, quality assurance teams in pharmaceuticals and materials, environmental testing labs, and anyone needing standardised zeta‑potential measurements for colloidal systems.

Q: Is it current or superseded?

A: ISO 13099-2:2025 is the current (published) edition; it supersedes and replaces ISO 13099-2:2012.

Q: Is it part of a series?

A: Yes — it is Part 2 of the ISO 13099 series. Part 1 (ISO 13099‑1) provides theoretical models and electroacoustic/electrokinetic methods that are used together with Part 2 for a complete zeta‑potential determination framework.

Q: What are the key keywords?

A: zeta potential; electrophoretic mobility; electrophoretic light scattering; video microscopy; colloidal systems; particle characterisation; ISO 13099.