ABSTRACT
Conductivity analyzers measure ionic concentration of electrolyte samples. Cells and instrumentation are designed to measure the electrical resistance in a volume element of the electrolyte and to limit electrode/solution interfacial contributions to this measurement. Since the intent is only to measure the bulk conductivity of the electrolyte, the interfacial impedance of the electrodes with the solution must be minimized. Particularly noteworthy is the class of two-electrode conductivity applications, called resistivity measurements, which employ titanium two-electrode cells in monitoring the high-purity water used in semiconductor manufacture, steam turbines, and nuclear reactors. Four-electrode conductivity is useful for high conductance when coating and fouling of electrodes is of concern. Conductivity measuring systems may be designed to be trouble-free and produce reliable measurements; however, some maintenance may be required, especially of the electrode. Composition measurement using conductivity is popular for industrial process measurement and control because of the inherent simplicity and reliability of the technique when it is applicable.
