Is there one technology for generating the most accurate particle characterization result?

Each particle characterization technique “sees” the same system differently due to differences in “weighting factors.” The mean value summarized from discrete individual values represents the relationship between the measured signal and the particle.

It’s important to understand the differences in technologies to obtain particle size. When using an electron microscope to measure particles, it will measure the diameters, add them and divide by the number of particles to calculate a mean result. A laser diffraction instrument calculates size mean data from multiple diffraction patterns of many particles at the same time. With the Coulter Principle (or Electric Sensing Zone Method), the volume of each individual particle is determined and the result is reported as the Heywood diameter.

For example, a particle system of four spherical particles with respective diameters of 1, 2, 3 and 10 μm will generate different corresponding mean values based on technique.

  • Method Mean Diameter μm
  • Electron Microscopy 4.0
  • Coulter Method 6.37
  • Laser Diffraction 9.74