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Particle Size Analysis utilizing a COULTER MULTISIZER IIe or III

The Coulter Principle, also known as ESZ (Electrical Sensing Zone Method), the Multisizer IIe and 3 Coulter Counter provides number, volume, mass and surface area size distributions in one measurement, with an overall sizing range of 0.4 to 1,200 microns (practical limits for most industrial powders are from 0.06 to 200 microns). Its response is unaffected by particle color, shape, composition or refractive index.

Particles suspended in a weak electrolyte solution are drawn through a small aperture, separating two electrodes between which an electric current flows. The voltage applied across the aperture creates a “sensing zone”. As particles pass through the aperture (or “sensing zone”), they displace their own volume of electrolyte, momentarily increasing the impedance of the aperture.

This change in impedance produces a pulse that is digitally processed in real time. The Coulter Principle states that the pulse is directly proportional to the tri-dimensional volume of the particle that produced it. Analyzing these pulses enables a size distribution to be acquired and displayed in volume (µm3 or fL) and diameter (µm). In addition, a metering device is used to draw a known volume of the particle suspension through the aperture; a count of the number of pulses can then yield the concentration of particles in the sample.

  • High density materials requiring an increased viscosity electrolyte are subject to an additional fee per sample.
  • Conductive materials such as carbon, metal powder, etc. are subject to an additional fee per sample.
  • Materials that are soluble in water and require special electrolytes are subject to an additional fee per sample.
  • We will need approximately one gram or more of sample to perform a particle size analysis.