Laser Diffraction by Mastersizer 3000, Malvern
Laser diffraction is a popular particle sizing technique because it offers a number of advantages. However, laser diffraction is not without its challenges. Sampling errors can vary the results in any particle sizing research — particularly when measuring larger particles.
Wide and dynamic range. In measuring particle size, a reliable analytical instrument will allow the user to measure particles between approximately 0.01 to 3500 microns in size.
Sample measured. This technique allows for the whole of the sample to be measured. As the sample passes through the laser beam, diffraction is measured for all particles.
One of the biggest challenges for laser diffraction methods is getting a representative sample out of a larger bulk product.
Sampling errors are the largest source of variation in any particle sizing experiment (including laser diffraction), especially when it involves measurement of larger particles.
It’s also essential that the sample preparation method is tailored to the material being measured. Particularly, one must choose between wet and dry dispersion, with aspects such as the natural state of the sample, its potential to be dispersed and the volume of the sample all coming into consideration. Wet dispersion is the most commonly used method due to its suitability for a wider range of samples.