The HI4114-51 potassium module is for use with the HI4114 potassium combination ion selective electrode (ISE). The liquid membrane sensor is comprised of a valinomycin-containing polymer within an inert PVC matrix. The sensor is responsible for the exchange of potassium ions across the membrane. A charge imbalance develops between the sample and the internal cell in response to the potassium ion activity. The potential change is proportional to the concentration of ions in solution.

The HI4114-51 potassium combination module easily screws onto the HI4114 probe body, allowing for quick assemblage or replacement. Presoaking the potassium sensor in a dilute standard without ionic strength adjuster (ISA) for at least one half hour before calibration will help to optimize the sensor response. Refrigeration of the HI4114-51 potassium module will help extend its life.