scope:

This International Standard specifies the application of dynamic light scattering (DLS) to the measurement of average hydrodynamic particle size and the measurement of the size distribution of mainly submicrometre-­‐sized particles, emulsions or fine bubbles dispersed in liquids. DLS is also referred to as quasi-­‐elastic light scattering (QELS) and photon correlation spectroscopy (PCS), although it actually is one of the measurement techniques. This International Standard is applicable to the measurement of a broad range of dilute and concentrated suspensions. The principle of dynamic light scattering for a concentrated suspension is the same as for a dilute suspension. However, specific requirements for the instrument set-­‐up and specification of test sample preparation are required for concentrated suspensions. At high concentrations, particle-­‐particle interactions and multiple light scattering can become dominant and may result in apparent particle sizes that differ between concentrated and dilute suspensions.