Chloride ISE Maintenance

 All crystalline ISEs do start to develop an oxidised layer on the crystal after a period of time. If the electrode is immersed for a long time it also gets a little soft on the outer layer.
Image showing some Mini Ion Selective Electrodes.
Image showing a combination Ion Selective Electrode.

 All you need do is dry the grey crystal surface and rub it down very gently with a very fine emery cloth or paper. The finer the better. This will reinstate its performance back to what it was. Clean thoroughly afterwards to remove the loose dust.

NB: You can do this with all crystalline ISEs e.g. Chloride, Bromide, Copper etc. but you cannot do this with PVC based ISEs e.g. Nitrate, Potassium Ammonium etc.