Low-frequency dielectric spectroscopy of colloidal suspensions

The main difficulties related to low-frequency dielectric measurements of liquid conducting samples using impedance analyzers such as the HP 4192 A or HP 4284 A are presented and discussed. These include the small value of the phase angle and the electrode polarization impedance. We propose ways to overcome these difficulties in terms of cell design, choice of instrument settings, choice of electrode material, connection of the cell to the instrument. We also propose a new calibration method that allows a differential measurement of the dielectric properties with far higher precision than possible using the standard short–open calibration.