The HI4113-53 nitrate module is for use with the HI4113 nitrate combination ion selective electrode (ISE). The liquid membrane sensor contains an organic polymer within the inert PVC matrix that is responsible for exchange of nitrate ions across the membrane. A charge imbalance develops between the sample and the internal cell in response to the nitrate ion activity. The potential change is proportional to the concentration of ions in solution.

The HI4113-53 nitrate combination module easily screws onto the HI4113 probe body, allowing for quick assemblage or replacement. Presoaking the nitrate 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 HI4113-53 nitrate module will help extend its life.