Care and Maintenance of ISE Probes
Proper use and care of your ISE electrodes is critical to ensuring that they continue to function properly. There are three main precautions you can take to ensure long life and accurate measurements: keep the ISE filled with electrolyte fill solution, store the electrodes properly, and replace the membrane when needed.
1. Fill the ISE with electrolyte fill solution
One of the most important aspects of electrodes is the reference fill solution. Taking care to use the correct solution and keeping it well filled will ensure you maintain a good fill solution flow rate.
Always be sure to check your fill solution level before use. The fill solution level should not be less than 2-3 cm (about 1 inch) below the fill hole. Additionally, the filler cap should always be removed prior to calibration and measurement. Adding enough electrolyte helps maintain adequate head pressure and a consistent flow rate, which produces the most accurate measurements. Most nitrate ISEs use ammonium sulfate electrolyte as the fill solution.
2. Properly store electrodes
Proper electrode storage will help extend the sensor life of the electrode.