Exchange between phases, simple waves

The conductivity detector is based on the ability of ions to conduct electricity across two electrodes in a flow cell between which an electric field is applied. The current measures is proportional to the conductivity of the solution. Usually a sinusoidal wave potential is applied to the electrodes and the only current measured is that in phase with the applied potential. Most conductivity detectors for HPLC can be set electronically to compensate for the background eluent conductivity. In addition, because the mobility of ions varies with solution temperature, a thermistor is mounted close to the cell to permit electronic compensation. The conductivity detector has proved to be important for ion-exchange HPLC of simple inorganic and organic ions. 

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