Measurement of the Low-Frequency Dielectric Properties of Colloidal Suspensions: Comparison between Different Methods.

A careful analysis of the main factors that affect the low-frequency dielectric measurements of conducting liquid samples is carried out. The influence of the type of the measurement cell, the calibration method, and the type of the instrument used, on the spectra obtained using the variable electrode spacing technique, is investigated. Permittivity and conductivity measurements in the 10 Hz to 10 MHz range are reported for low (sigma approximately 0.01 S/m) and high (sigma approximately 0.7 S/m) conductivity samples, both electrolyte solutions and polystyrene particle suspensions. Two measurement cells are evaluated: one made of glass currently used at Granada and the other made of acrylic currently used at Tucumán. Two calibration methods, the classical Short/Open correction and the quadrupolar technique (similar to the Short/Open/Load correction), are contrasted, and two impedance analyzers, the HP 4284 A and the HP 4192 A, are compared. Copyright 2000 Academic Press.