This document specifies the principles of particle size analysis by centrifugal liquid sedimentation (CLS). It also:

— defines the relevant terms;

— describes the various measurement techniques;

— gives guidance for sample preparation, conducting measurements as well as data analysis;

— establishes rules for method validation, determination of the uncertainty budget as well as representation of results.

An important part of this document deals with the derivation of particle size distributions from CLS data, including discussions on:

— the impact of Brownian motion;

— the parallel determination of particle concentrations;

— the working range with respect to size and concentration;

—the handling of non-spherical and porous particles.

This document applies to samples composed of dispersions of low particle concentration, so that the particles’ motion can be considered as that of fully isolated particles. This document does not cover particle migration by gravity, electric or magnetic forces. It also does not cover deriving particle properties other than size, sedimentation velocity and sedimentation coefficient.

NOTE            This document can involve hazardous materials, operations and equipment. It does not purport to address all the safety problems associated with its use. Regulations regarding explosion-proof analysers can apply when examining volatile liquids with a low flash point. It is the responsibility of the user of this document to establish appropriate safety and health practices and to determine the applicability of the regulatory limitations prior to its use.