A high-accuracy, calibration-free technique for measuring the electrical conductivity of liquids

A high-accuracy, calibration-free technique to measure the electrical conductivity of liquids has been developed — the coaxial cylinders technique. Because the liquid under investigation comes in contact only with metal and not with anything dielectric, this technique enables the measurement of the electrical properties of liquids inaccessible by classical high-accuracy techniques. Two coaxial cylindrical electrodes are immersed in the liquid to an arbitrary initial depth, and ac impedance is measured over a wide range of frequency. This process is repeated at many immersions. The electrical conductivity is calculated from the change in measured conductance with immersion. This technique was validated in 1.0, 0.1, and 0.01 D KCl(aq) solutions at room temperature. Measured electrical conductivities were within ±0.5% of the standard reference values.