In electrical sensing zone an electrolyte solution is used to disperse and count particles. A tube with a known narrow aperture is submerged in the solution and two electrodes are placed on both sides of the aperture.

Electrolyte and particles travel through the aperture and the resistance proportional to the particle volume is measured. Each individual particle is counted and categorized in the appropriate size class. The Electrical sensing zone technique is in principle a particle counter and can also be used to measure particle concentrations.

The technique is used for particle characterization and particle counting in narrow particle size distributions, typically within the range of 0.6 to 1200 µm. Particles in low concentration solutions, powders and biological matter are typically analyzed.

The measurements are performed on a Coulter Multisizer II or Multisier III particle analyser. The report consists of a graph showing the cumulative and differential particle volume or number distributions and information on the particle statistics as the mode, mean and median particle diameter, skew ness and kurtosis, standard deviation etc.