07 Feb

Ion Selective Electrodes

You need to detect Chloride ion in your samples?  If you need a precise determination a Chloride ion selective electrode may be the tool you need.  Ion Selective electrodes, or ISE’s, are designed for many ions:  Cl-, F-, Br-, NH4+,  NO3+,  K+,  and Na+ are a few examples.  Other molecules can also be determined such as O2 and NH3. These probes have membranes which are sensitive to a specific ion or molecule.  For instance a Fluoride ion selective electrode has a membrane of LaF3.  ISE’s are available as combination electrodes or as half cells to be used with a reference electrode.  If you have many samples daily which need an ion determination the ISE may be the right tool for your lab.   The samples will need special preparation such as the addition of an ionic strength adjustment buffer or ISAB.  Also standards would need to be prepared and the instrument calibrated daily.  There is also some maintenance involved with an ISE.  Many manufacturers provide kits with an ISE meter and probe, a pH probe, and a stand.  Field kits are also available.  If you are handling many ion determinations daily and you need precise results, the ISE can save time and reagents.

Robin Prymula