This document specifies the particle tracking analysis (PTA) method under static (no flow) conditions for the determination of the number–based particle size distribution and the number concentration in liquid dispersions (solid particles, liquid droplets or bubbles suspended in liquids).

This document covers two tracking regimes.

— Brownian motion tracking for smaller particles.

— Gravitational fall tracking for larger particles.

This document outlines the theory and basic principles of the PTA method along with its limitations and advantages for both size evaluation and number concentration measurements. It also describes commonly used instrument configurations and measurement procedures as well as system qualifications and data reporting.