Improved calibration of impedance analyzers for measurements on highly conductive liquids

An improved calibration method for low-frequency dielectric measurements of conducting liquids using an impedance analyzer is presented. It consists of representing the instrument as an electric quadrupole and performing three calibrations over the whole frequency range. These calibrations consist of short, open, and a reference load whose impedance is similar to that of the unknown sample. The reference load consists of the sample cell filled with an electrolyte with known dielectric properties. This method allows a differential measurement of the dielectric properties of the unknown liquid with far higher precision than what is possible using the standard calibration method. It proved useful for measurements on suspensions of up to 0.8 S/m conductivity at frequencies down to 10 kHz using the Hewlett Packard HP 4192 A instrument.